WO2026020937A1 - Procédé de communication sans fil et appareil de communication - Google Patents

Procédé de communication sans fil et appareil de communication

Info

Publication number
WO2026020937A1
WO2026020937A1 PCT/CN2025/094698 CN2025094698W WO2026020937A1 WO 2026020937 A1 WO2026020937 A1 WO 2026020937A1 CN 2025094698 W CN2025094698 W CN 2025094698W WO 2026020937 A1 WO2026020937 A1 WO 2026020937A1
Authority
WO
WIPO (PCT)
Prior art keywords
terminal device
cell
candidate cell
message
identifier
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
PCT/CN2025/094698
Other languages
English (en)
Chinese (zh)
Inventor
唐晓璇
刘旭
潘晓刚
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Honor Device Co Ltd
Original Assignee
Honor Device Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Honor Device Co Ltd filed Critical Honor Device Co Ltd
Publication of WO2026020937A1 publication Critical patent/WO2026020937A1/fr
Pending legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/0005—Control or signalling for completing the hand-off
    • H04W36/0011—Control or signalling for completing the hand-off for data sessions of end-to-end connection
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/0005—Control or signalling for completing the hand-off
    • H04W36/0055—Transmission or use of information for re-establishing the radio link
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/0005—Control or signalling for completing the hand-off
    • H04W36/0055—Transmission or use of information for re-establishing the radio link
    • H04W36/0072—Transmission or use of information for re-establishing the radio link of resource information of target access point
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/08—Reselecting an access point
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/34—Reselection control
    • H04W36/36—Reselection control by user or terminal equipment
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/34—Reselection control
    • H04W36/36—Reselection control by user or terminal equipment
    • H04W36/362—Conditional handover

Definitions

  • This application relates to the field of communications, and more particularly to a wireless communication method and communication device.
  • terminal devices can perform uplink synchronization with candidate cells in advance.
  • the network device can send a handover command to the terminal device, carrying the timing advance (TA) of the candidate cell in the handover command.
  • the terminal device can directly handover to the corresponding candidate cell based on the TA of the candidate cell.
  • TA timing advance
  • a conditional handover mechanism is introduced.
  • the terminal device can determine whether a candidate cell meets the handover conditions based on pre-configured handover criteria. If a candidate cell meets the handover conditions, the terminal device hands over to that candidate cell.
  • network devices may not send handover commands to terminal devices.
  • terminal devices may not send handover commands to terminal devices.
  • TA target cell's transfer information
  • This application provides a wireless communication method and a communication device, which provides a clear scheme for terminal devices to obtain the TA of candidate cells.
  • a wireless communication method comprising: receiving first information sent by a network device, the first information being used to determine reception parameters for a first timing advance TA, the first TA being a TA for a first candidate cell, the first candidate cell being a cell different from the serving cell; and receiving the first TA based on the first information.
  • the network device can send first information related to the first TA (i.e., the TA of the candidate cell) reception parameters to the terminal device.
  • the terminal device can determine the first TA reception parameters based on the first information and receive the first TA using these parameters. Therefore, the solution in this embodiment enables the terminal device to obtain the first TA of the candidate cell using the first TA reception parameters.
  • the first information includes first configuration information, which includes TA receiving parameters corresponding to one or more cells, and the one or more cells include the first candidate cell; receiving the first TA based on the first information includes: determining the receiving parameters of the first TA based on the first configuration information; and receiving the first TA based on the receiving parameters of the first TA.
  • This application embodiment can reduce the complexity of the terminal device determining the first TA reception parameter by configuring the TA reception parameters corresponding to the cell for the terminal device. Furthermore, the first configuration information can be used to configure TA reception parameters corresponding to multiple cells for the terminal device, meaning that TA reception parameters for multiple cells can be configured for the terminal device at once, reducing signaling overhead.
  • the first configuration information includes a first identifier and TA receiving parameters corresponding to the first identifier, wherein the TA receiving parameters corresponding to the first identifier include the receiving parameters of the first TA.
  • determining the reception parameters of the first TA based on the first configuration information includes: determining the reception parameters of the first TA based on the first identifier corresponding to the first candidate cell and the TA reception parameters corresponding to the first identifier.
  • This application embodiment configures a first identifier and corresponding TA receiving parameters for the terminal device, enabling the terminal device to determine the correspondence between the first identifier and the TA receiving parameters. This allows the terminal device to determine the receiving parameters of the first TA based on this correspondence. This reduces the complexity of the terminal device determining the TA receiving parameters.
  • the method further includes: receiving first indication information sent by the network device, the first indication information being used to indicate the first identifier corresponding to the receiving parameters of the first TA.
  • the terminal device can determine the reception parameters of the first TA based on the first indication message and the TA reception parameters corresponding to the first identifier.
  • the network device can send the first indication message to the terminal device only when it needs the terminal device to receive the first TA. This allows the terminal device to receive the TA according to actual needs, avoiding invalid reception and wasting communication resources.
  • the first indication information is carried in a PDCCH order.
  • the first configuration information further includes the first identifier corresponding to the candidate cell
  • the step of determining the reception parameters of the first TA based on the first configuration information includes: determining the reception parameters of the first TA based on the first identifier corresponding to the candidate cell and the TA reception parameters corresponding to the first identifier.
  • the embodiments of this application can directly configure the first identifier corresponding to the candidate cell for the terminal device, so that the terminal device can determine the receiving parameters of the first TA on its own according to the first configuration information, without the need for additional instructions from the network device, thereby reducing signaling overhead.
  • the first identifier includes any one of the following: the identifier of the network unit to which the candidate cell belongs; or an identifier indicating whether the candidate cell and the serving cell belong to the same network unit.
  • the embodiments of this application determine the first identifier based on the network unit, which can reduce the number of TA receiving parameters that need to be configured for the terminal device, thereby reducing resource overhead.
  • the network unit is a CU.
  • the first identifier includes the index of the TA receive parameters and/or the identifier of the candidate cell.
  • the first configuration information includes configuration information of the one or more cells, and the configuration information of the one or more cells respectively includes TA receiving parameters corresponding to the one or more cells.
  • the correspondence between the TA receiving parameters and the cell can be implicitly included. This eliminates the need for additional configuration of the correspondence between the TA receiving parameters and the cell, which helps reduce transmission overhead.
  • the cell's configuration information is the cell's early TA configuration.
  • the method before receiving the first TA, the method further includes: receiving a first message sent by the network device, the first message being used to trigger the terminal device to receive the first TA.
  • the terminal device is triggered to receive the first TA by the first message, which can avoid the terminal device receiving invalid TA and save the terminal device's power.
  • the first message includes the identification information of the first candidate cell and/or the configuration information of the first candidate cell.
  • the terminal device can clearly identify which candidate cell's TA needs to be received this time, and thus receive the TA at the receiving location corresponding to that candidate cell, thereby achieving accurate TA reception.
  • the method before receiving the first TA, further includes: receiving a second message sent by the network device, the second message being used to trigger the terminal device to send a preamble to the first candidate cell; receiving the first TA includes: if the first message is the same as the second message and/or the first message contains second indication information, then receiving the first TA, wherein the second indication information is used to instruct the terminal device to receive the first TA.
  • Network devices can trigger terminal devices to receive the first TA by sending the same message to the terminal device (i.e., the first message and the second message are the same) or by directly carrying indication information in the first message. This method requires less modification to the protocol and can reduce the complexity of communication.
  • the second message includes third indication information, which indicates that there is a subsequent reception indication for the first TA.
  • the terminal device can distinguish the scheme of this application from the random access procedure in related technologies, allowing the terminal device to clearly understand the operation flow after sending the preamble. For example, in related technologies, if the second message does not carry the third indication, the random access procedure ends after the terminal device sends the preamble, and the terminal device does not need to receive the first TA or listen to the RAR. In the scheme of this application, the second message carries the third indication, allowing the terminal device to wait for instructions from the network device after sending the preamble to receive the first TA or listen to the RAR.
  • both the first message and the second message are Physical Downlink Control Channel (PDCCH) commands.
  • PDCCH Physical Downlink Control Channel
  • the first information includes fourth indication information, which is used to indicate the receiving parameters of the first TA.
  • the network device can directly indicate the reception parameters of the first TA to the terminal device, thereby reducing the complexity of obtaining the TA reception parameters. For example, if the network device receives a TA sent by a candidate cell, the network device can indicate the TA reception parameters for that candidate cell to the terminal device, and the terminal device can directly use the TA reception parameters to receive the TA.
  • the reception parameters of the first TA are sent from the first candidate cell to the network device.
  • the first candidate cell sends the reception parameters of the first TA to the network device, so that the network device can know the transmission location of the first TA or the RAR window carrying the first TA, so as to avoid scheduling the terminal device at that location or RAR window, thereby avoiding the impact on the scheduling of the network device.
  • the first TA is carried in the Random Access Response (RAR) or the Media Access Control (MAC) control element (CE).
  • RAR Random Access Response
  • MAC Media Access Control
  • the first TA is carried within the RAR, which allows the TA acquisition process to match the random access process with minimal protocol modifications, thus reducing communication complexity.
  • the first TA is carried within the MAC CE, allowing terminal devices to directly acquire the TA by receiving the MAC CE without needing to listen to the RAR window, further reducing communication overhead.
  • the first TA is carried in a RAR
  • the receiving parameters of the first TA include a RAR response window and/or a delay time.
  • the RAR response window is a window for listening to the RAR carrying the first TA
  • the delay time is the time interval between the start position of the RAR response window and the transmission position of the preamble.
  • the preamble is a preamble sent by the terminal device to the first candidate cell.
  • the terminal device can clearly listen to the location of the RAR, thereby enabling more accurate reception of the first TA.
  • the receiving parameters of the first TA include the delay time and the length of the RAR reply window.
  • the receiving parameters of the first TA include one or more of the following: the start position of the RAR reply window, the window length, and the end position.
  • the RAR response window is a periodic window
  • the first information includes one or more of the following: the starting position of the periodic window, the number of periods, and the period length.
  • multiple candidate cells can share the same RAR response window, eliminating the need to configure a separate RAR response window for each candidate cell and reducing the complexity of RAR response window configuration.
  • the MAC CE includes identification information of the first candidate cell and/or indication information on whether it is applied to mobility LTM triggered based on layer L1/L2.
  • the terminal device can clearly identify which candidate cell the received TA is for, thereby better realizing subsequent cell handover.
  • the identification information of the first candidate cell is carried in the TI field of the MAC CE, and/or the indication information of whether it is applied to LTM is carried in the R field.
  • receiving the first TA includes: receiving the first TA sent by the serving cell; or receiving the first TA sent by the first candidate cell.
  • a wireless communication method comprising: sending first information to a terminal device, the first information being used to determine reception parameters for a first timing advance TA, the first TA being a TA for a first candidate cell, the first candidate cell being a cell different from the serving cell.
  • the first information includes first configuration information, which includes TA (Transmission Attack) reception parameters corresponding to one or more cells, wherein the one or more cells include the first candidate cell, and the reception parameters of the first TA are determined based on the first configuration information.
  • TA Transmission Attack
  • the first configuration information includes a first identifier and TA receiving parameters corresponding to the first identifier, wherein the TA receiving parameters corresponding to the first identifier include the receiving parameters of the first TA.
  • the method further includes: sending first indication information to the terminal device, the first indication information being used to indicate the first identifier corresponding to the receiving parameters of the first TA.
  • the first indication information is carried in a PDCCH order.
  • the first configuration information further includes the first identifier corresponding to the candidate cell.
  • the first identifier corresponding to the candidate cell, and the TA receiving parameters corresponding to the first identifier, are used to determine the first TA.
  • the first identifier includes any one of the following: the identifier of the network unit to which the candidate cell belongs; or an identifier indicating whether the candidate cell and the serving cell belong to the same network unit.
  • the network unit is a CU.
  • the first identifier includes the index of the TA receive parameters and/or the identifier of the candidate cell.
  • the first configuration information includes configuration information of the one or more cells, and the configuration information of the one or more cells respectively includes TA receiving parameters corresponding to the one or more cells.
  • the cell's configuration information is the cell's early TA configuration.
  • the method further includes: sending a first message to the terminal device, the first message being used to trigger the terminal device to receive the first TA.
  • the first message includes the identification information of the first candidate cell and/or the configuration information of the first candidate cell.
  • the method further includes: sending a second message to the terminal device, the second message being used to trigger the terminal device to send a preamble to the first candidate cell; wherein the first message is the same as the second message, and/or the first message contains second indication information, the second indication information being used to instruct the terminal device to receive the first TA.
  • the second message includes third indication information, which indicates that there is a subsequent reception indication for the first TA.
  • both the first message and the second message are Physical Downlink Control Channel (PDCCH) commands.
  • PDCCH Physical Downlink Control Channel
  • the first information includes fourth indication information, which is used to indicate the receiving parameters of the first TA.
  • the reception parameters of the first TA are sent from the first candidate cell to the network device.
  • the first TA is carried in the Random Access Response (RAR) or the Media Access Control (MAC) control element (CE).
  • RAR Random Access Response
  • MAC Media Access Control
  • the first TA is carried in a RAR
  • the receiving parameters of the first TA include a RAR response window and/or a delay time.
  • the RAR response window is a window for listening to the RAR carrying the first TA
  • the delay time is the time interval between the start position of the RAR response window and the transmission position of the preamble.
  • the preamble is a preamble sent by the terminal device to the first candidate cell.
  • the receiving parameters of the first TA include the delay time and the length of the RAR reply window.
  • the receiving parameters of the first TA include one or more of the following: the start position of the RAR reply window, the window length, and the end position.
  • the RAR response window is a periodic window
  • the first information includes one or more of the following: the starting position of the periodic window, the number of periods, and the period length.
  • the MAC CE includes identification information of the first candidate cell and/or indication information on whether it is applied to mobility LTM triggered based on layer L1/L2.
  • the identification information of the first candidate cell is carried in the TI field of the MAC CE, and/or the indication information of whether it is applied to LTM is carried in the R field of the MAC CE.
  • the method further includes: receiving the reception parameters of the first TA sent by the first candidate cell; or sending the reception parameters of the first TA to the first candidate cell.
  • a wireless communication method comprising: receiving a MAC CE sent by a network device, wherein the MAC CE includes a first TA for a first candidate cell, the first candidate cell being a cell different from the serving cell.
  • Network devices can indicate the first TA to terminal devices via MAC CE. In this way, terminal devices can obtain the first TA directly by receiving MAC CE without needing to determine the TA's reception parameters.
  • the MAC CE includes identification information of the first candidate cell and/or indication information on whether it is applied to mobility LTM triggered based on layer L1/L2.
  • the terminal device can clearly identify which candidate cell the received TA is for, thereby better realizing subsequent cell handover.
  • the identification information of the first candidate cell is carried in the TI field of the MAC CE, and/or the indication information of whether it is applied to LTM is carried in the R field.
  • the method further includes sending a preamble to the first candidate cell before receiving the MAC CE sent by the network device.
  • a wireless communication method comprising: sending a MAC CE to a terminal device, wherein the MAC CE includes a first TA for a first candidate cell, the first candidate cell being a cell different from the serving cell.
  • the MAC CE includes identification information of the first candidate cell and/or indication information on whether it is applied to mobility LTM triggered based on layer L1/L2.
  • the identification information of the first candidate cell is carried in the TI field of the MAC CE, and/or the indication information of whether it is applied to LTM is carried in the R field.
  • a communication device comprising a unit composed of software and/or hardware, the unit being configured to perform any one of the methods in the first aspect or any one of the methods in the third aspect.
  • a communication device comprising a unit composed of software and/or hardware, the unit being configured to perform any one of the methods in the second aspect or any one of the methods in the fourth aspect.
  • a chip including a processor; the processor is configured to read and execute a computer program stored in a memory to perform any one of the methods described in the first aspect, or to perform any one of the methods described in the third aspect.
  • the chip further includes a memory, which is connected to the processor via a circuit or wire.
  • the chip may further include a communication interface.
  • a chip including a processor; the processor is configured to read and execute a computer program stored in a memory to perform any one of the methods described in the second aspect, or to perform any one of the methods described in the fourth aspect.
  • the chip further includes a memory, which is connected to the processor via a circuit or wire.
  • the chip may further include a communication interface.
  • a terminal device comprising: a processor, a memory, and an interface; the processor, the memory, and the interface cooperate with each other to enable the terminal device to execute any one of the technical solutions described in the first aspect, or to execute any one of the technical solutions described in the third aspect; or to include any one of the chips described in the seventh aspect.
  • a network device comprising: a processor, a memory, and an interface; the processor, the memory, and the interface cooperate with each other to enable the network device to execute any one of the technical solutions described in the second aspect, or to execute any one of the technical solutions described in the fourth aspect; or to include any one of the chips described in the eighth aspect.
  • a computer-readable storage medium wherein a computer program is stored therein, and when the computer program is executed by a processor, the processor performs any one of the methods of the technical solutions described in any one of the first to fourth aspects.
  • a computer program product comprising: computer program code, which, when run on an electronic device, causes the electronic device to perform any one of the technical solutions described in any one of the first to fourth aspects.
  • Figure 1 is a schematic diagram of a communication system provided in an embodiment of this application.
  • Figure 2 is a schematic flowchart of a random access method
  • Figure 3 is a schematic diagram of the temporal relationship between a terminal device sending a preamble and listening to RAR;
  • Figure 4 is a schematic diagram of a MAC CE structure
  • Figure 5 is a schematic flowchart of a cell handover based on L3;
  • FIG. 6 is a schematic diagram of an LTM switching process
  • FIG. 7 illustrates several cell handover scenarios
  • Figure 8 is a schematic flowchart of a cell handover within the same CU
  • Figure 9 is a schematic flowchart of a terminal device performing random access with a candidate cell
  • Figure 10 is a schematic diagram of a terminal device obtaining a RAR for a candidate cell according to an embodiment of this application;
  • Figure 11 is a schematic flowchart of a wireless communication method provided in an embodiment of this application.
  • Figure 12 is a schematic diagram of the location of a terminal device monitoring the RAR provided in an embodiment of this application;
  • Figure 13a is a schematic diagram of the structure of a MAC CE carrying a candidate cell TA provided in an embodiment of this application;
  • Figure 13b is a schematic diagram of another MAC CE carrying a candidate cell TA provided in an embodiment of this application;
  • Figure 13c is a schematic diagram of another MAC CE carrying a candidate cell TA provided in an embodiment of this application.
  • FIG. 14 is a schematic flowchart of another wireless communication method provided in an embodiment of this application.
  • Figure 15 is a schematic block diagram of a communication device provided in an embodiment of this application.
  • Figure 16 is a schematic block diagram of another communication device provided in an embodiment of this application.
  • Figure 17 is a schematic block diagram of another communication device provided in an embodiment of this application.
  • Figure 18 is a schematic block diagram of another communication device provided in an embodiment of this application.
  • Figure 19 is a schematic diagram of the structure of a device provided in an embodiment of this application.
  • FIG 1 is a schematic diagram of the architecture of the communication system 1000 used in an embodiment of this application.
  • the communication system includes a radio access network (RAN) 100, wherein the RAN 100 includes at least one RAN node (110a and 110b in Figure 1, collectively referred to as 110), and may also include at least one terminal device (120a-120j in Figure 1, collectively referred to as 120).
  • the RAN 100 may also include other RAN nodes, such as wireless relay devices and/or wireless backhaul devices (not shown in Figure 1).
  • the terminal device 120 is wirelessly connected to the RAN node 110. Terminal devices and RAN nodes can be interconnected via wired or wireless means.
  • the communication system 1000 may also include a core network 200.
  • the RAN node 110 is connected to the core network 200 via wireless or wired means.
  • the core network equipment in core network 200 and the RAN node 110 in RAN 100 can be independent and different physical devices, or they can be the same physical device that integrates the logical functions of the core network equipment and the logical functions of the RAN node.
  • Communication system 1000 may also include Internet 300.
  • RAN 100 can be an evolved universal terrestrial radio access (E-UTRA) system, a new radio (NR) system, or a future radio access system as defined in the 3rd generation partnership project (3GPP).
  • RAN 100 can also be an open RAN (O-RAN or ORAN), a cloud radio access network (CRAN), or a wireless fidelity (WiFi) system.
  • RAN 100 can also include two or more of the above-mentioned different radio access systems.
  • RAN nodes also known as radio access network equipment, RAN entities, or access nodes, are used to help terminal devices access communication systems wirelessly.
  • an RAN node can be a base station, an evolved NodeB (eNodeB), a transmission reception point (TRP), a next-generation NodeB (gNB) in 5G mobile communication systems, a next-generation base station in 6G mobile communication systems, or a base station in future mobile communication systems.
  • RAN nodes can be macro base stations (as shown in Figure 1, 110a), micro base stations or indoor stations (as shown in Figure 1, 110b), and can also be relay nodes or donor nodes.
  • a RAN node can be a central unit (CU), a distributed unit (DU), or a radio unit (RU).
  • the CU performs the functions of the base station's Radio Resource Control (RRC) and Packet Data Convergence Protocol (PDCP), and can also perform the functions of the Service Data Adaptation Protocol (SDAP).
  • RRC Radio Resource Control
  • PDCP Packet Data Convergence Protocol
  • SDAP Service Data Adaptation Protocol
  • the DU performs the functions of the base station's Radio Link Control (RANC) and Medium Access Control (MAC) layers, and can also perform some or all of the physical layer functions.
  • RRC Radio Resource Control
  • PDCP Packet Data Convergence Protocol
  • SDAP Service Data Adaptation Protocol
  • the DU performs the functions of the base station's Radio Link Control (RANC) and Medium Access Control (MAC) layers, and can also perform some or all of the physical layer functions.
  • RRC Radio Resource Control
  • MAC Medium Access Control
  • the RU can be used to implement radio frequency signal transmission and reception.
  • the CU and DU can be two independent RAN nodes, or they can be integrated into the same RAN node, such as within a baseband unit (BBU).
  • RUs can be included in radio frequency equipment, such as remote radio units (RRUs) or active antenna units (AAUs).
  • RRUs remote radio units
  • AAUs active antenna units
  • CUs can be further divided into two types of RAN nodes: CU-control plane and CU-user plane.
  • RAN nodes may have different names.
  • a CU can be called an open CU (O-CU)
  • a DU can be called an open DU (O-DU)
  • an RU can be called an open RU (O-RU).
  • the RAN nodes in the embodiments of this application can be implemented through software modules, hardware modules, or a combination of software and hardware modules.
  • a RAN node can be a server loaded with the corresponding software modules.
  • the embodiments of this application do not limit the specific technology or device form used in the RAN nodes.
  • a base station is used as an example of a RAN node in the following description.
  • a terminal device is a device with wireless transceiver capabilities, capable of sending signals to or receiving signals from a base station.
  • Terminal devices can also be referred to as terminals, user equipment (UE), mobile stations, mobile terminals, etc. They can be widely used in various scenarios, such as device-to-device (D2D), vehicle-to-everything (V2X) communication, machine-type communication (MTC), the Internet of Things (IoT), virtual reality, augmented reality, industrial control, autonomous driving, telemedicine, smart grids, smart furniture, smart offices, smart wearables, smart transportation, and smart cities.
  • Terminal devices can be mobile phones, tablets, computers with wireless transceiver capabilities, wearable devices, vehicles, airplanes, ships, robots, robotic arms, smart home devices, etc. The embodiments of this application do not limit the specific technologies or device forms used in the terminal devices.
  • Base stations and terminal equipment can be fixed or mobile. They can be deployed on land, including indoors or outdoors, handheld or vehicle-mounted; they can also be deployed on water; and they can be deployed on aircraft, balloons, and satellites. The embodiments of this application do not limit the application scenarios of the base stations and terminal equipment.
  • the helicopter or drone 120i in Figure 1 can be configured as a mobile base station.
  • 120i For terminal devices 120j that access the wireless access network 100 through 120i, 120i is a base station; however, for base station 110a, 120i is a terminal device. That is, 110a and 120i communicate via a wireless air interface protocol. Of course, 110a and 120i can also communicate via a base station-to-base station interface protocol. In this case, relative to 110a, 120i is also a base station. Therefore, both base stations and terminal devices can be collectively referred to as communication devices.
  • 110a and 110b in Figure 1 can be called communication devices with base station functions
  • 120a-120j in Figure 1 can be called communication devices with terminal functions.
  • Communication between base stations and terminal devices, between base stations, and between terminal devices can be conducted using licensed spectrum, unlicensed spectrum, or both simultaneously. Communication can be conducted using spectrum below 6 GHz, spectrum above 6 GHz, or both simultaneously.
  • the embodiments of this application do not limit the spectrum resources used for wireless communication.
  • the functions of the base station can be executed by modules (such as chips) within the base station, or by a control subsystem that includes base station functions.
  • This control subsystem, including base station functions can be a control center in the aforementioned application scenarios such as smart grids, industrial control, intelligent transportation, and smart cities.
  • the functions of the terminal device can be executed by modules (such as chips or modems) within the terminal device, or by a device that includes terminal device functions.
  • Terminal devices can obtain uplink synchronization with network devices through a random access procedure.
  • the random access involved in the embodiments of this application can be contention-based random access or non-contention-based random access, and the embodiments of this application do not specifically limit it in this way.
  • FIG. 2 is a flowchart of a contention-based random access method according to an embodiment of this application.
  • step S210 the terminal device sends message 1 (Msg1) during the random access process to the network device.
  • Msg1 may include a preamble.
  • the terminal device can select a random access channel (RACH) resource and a preamble, and transmit the selected preamble on the selected resource.
  • RACH random access channel
  • This RACH resource can also be called a physical random access channel (PRACH) resource.
  • PRACH physical random access channel
  • the network device can send RACH configuration information to the terminal device via broadcast.
  • the RACH configuration information may include configuration information for the RACH time-frequency resources and configuration information for the starting preamble root sequence.
  • the RACH configuration information can be carried in a system message.
  • the terminal device can determine the RACH resources and preamble based on the RACH configuration information.
  • step S220 the network device sends Msg2 to the terminal device.
  • This Msg2 can also be called a random access response (RAR).
  • RAR random access response
  • This Msg2 can be carried through the physical downlink control channel (PDCCH).
  • PDCH physical downlink control channel
  • the terminal device After the terminal device sends Msg1, it can open a RAR time window and monitor the PDCCH scrambled with random access-radio network temporary identifier (RA-RNTI) within the time window.
  • RA-RNTI random access-radio network temporary identifier
  • the RAR time window starts at the subframe from which the preamble is sent (if the preamble spans multiple subframes in the time domain, the last subframe is used for calculation) + 3 subframes.
  • the duration of the RAR time window is ra - ResponseWindowSize subframes, as shown in Figure 3.
  • the ra-ResponseWindowSize can be configured by the network device.
  • the size of ra-ResponseWindowSize can be any one of 1 slot, 2 slots, 4 slots, 8 slots, 10 slots, 20 slots, 40 slots, 80 slots, or 2560 slots.
  • the size of ra-ResponseWindowSize can also be other values, and this embodiment does not specifically limit this.
  • Msg2 may also include a preamble sent by the terminal device. If the terminal device receives a PDCCH scrambled with RA-RNTI and Msg2 contains its own preamble, the terminal device can consider that it has successfully received the random access response.
  • the terminal device can obtain the physical downlink shared channel (PDSCH) scheduled by the PDCCH.
  • the PDSCH contains the RAR.
  • the RAR can contain multiple pieces of information.
  • the RAR subheader may contain a backoff indicator (BI), which can be used to indicate the backoff time for retransmitting Msg1;
  • the random access preamble identification (RAPID) in the RAR indicates the index of the preamble received by the network device in response;
  • the payload in the RAR may contain a timing advance group (TAG), which can be used to adjust uplink timing;
  • the RAR may also include an uplink (UL) grant, used to schedule uplink resources for Msg3;
  • the RAR may also include a cell-radio network temporary identifier (C-RNTI), which the terminal device can use to decode the PDCCH of Msg4 for initial access.
  • C-RNTI cell-radio network temporary identifier
  • the terminal device sends Msg3 to the network device.
  • the terminal device can send Msg3 on a UL grant scheduled by the network device.
  • This Msg3 can also be called a Radio Resource Control (RRC) Connection Establishment Request message.
  • RRC Radio Resource Control
  • step S240 the network device sends Msg4 to the terminal device.
  • FIG 4 illustrates the structure of a RAR.
  • the RAR structure shown in Figure 4 may include a TA group identity (TAG ID, or TI) or reserved (R) field, a timing advance command, an uplink grant (UL grant), and a temporary C-RNTI.
  • TAG ID TA group identity
  • R reserved
  • C-RNTI a temporary C-RNTI.
  • Oct represents a byte, and one byte contains 8 bits.
  • terminal devices can maintain TAs for two transmission points (TRPs) simultaneously.
  • the terminal device sends a preamble to one of the neighboring cells.
  • the neighboring cell measures its TA and can then transmit the TA to the serving cell.
  • the serving cell can then send a Receiving Arrangement (RAR) to the terminal device, which carries the TA specific to the neighboring cell.
  • RAR Receiving Arrangement
  • the serving cell can indicate the TAs of two TRPs to the terminal device through two RARs.
  • Each RAR carries one TA and indicates the associated TAG ID through the reserved (R) field.
  • Cell handover aims to improve the continuity of service provided by a communication system to terminal devices.
  • a terminal device moves from one cell (also known as the "source cell") to another cell, it needs to hand over to the other cell (also known as the "target cell") to maintain communication.
  • the cell can be a primary cell (PCell) or a primary secondary cell (PSCell).
  • the source cell currently providing service to the terminal device can also be called the serving cell.
  • Terminal devices can perform cell handover in two ways: layer 3 (L3) based cell handover and L1/L2 based cell handover.
  • L1/L2 based cell handover can also be called L1/L2-triggered mobility (LTM) handover.
  • LTM L1/L2-triggered mobility
  • step S510 the terminal device sends an L3 measurement report to the source cell.
  • step S520 the source cell determines the cell handover to be performed by the terminal device based on the L3 measurement report.
  • the source cell can also select a target cell for the terminal device.
  • step S530 the source cell sends a handover request to the target cell.
  • step S540 the target cell sends a handover request response to the source cell.
  • step S550 the source cell sends an L3 handover command to the terminal device.
  • step S560 after receiving the L3 handover command, the terminal device establishes a connection with the target cell.
  • L3-based cell handover is triggered by L3 measurements and completed via RRC signaling.
  • L3-based handover requires reconfiguration of the RRC layer or the Packet Data Convergence Protocol (PDCP) layer, and resets the Medium Access Control (MAC) layer and/or the physical layer, which increases the complexity of the handover process and increases handover latency.
  • PDCP Packet Data Convergence Protocol
  • MAC Medium Access Control
  • LTM uses L1/L2 signaling to change the serving cell of the terminal device while maintaining the higher-layer configuration unchanged, which helps reduce latency, lower overhead, and shorten downtime.
  • the terminal device reports L1 measurement results based on the network configuration.
  • the network device can then make LTM decisions based on these results and send handover commands to the terminal device.
  • the terminal device can leave its current serving cell and attempt to access a target LTM cell.
  • the terminal device retains the configuration information of the LTM candidate cells after completing the handover to facilitate subsequent handovers.
  • the network device can send a handover command to the terminal device through a MAC control element (CE).
  • the handover command can be carried in the MAC CE.
  • LTM preparation stage steps S602 to S608
  • pre-synchronization stage step S610
  • LTM execution stage steps S612 to S618
  • LTM completion stage step S620
  • the terminal device can send a measurement report to the network device.
  • the terminal device in this embodiment can be a terminal device in RRC connected state.
  • the network device can be the source cell.
  • the measurement report may be based on L3 measurement, i.e., the measurement report is an L3 measurement report.
  • the network device can determine whether to initiate an LTM procedure based on the measurement report. If the network device determines to initiate an LTM procedure, it can trigger candidate cells to prepare for handover.
  • step S606 the network device sends an RRC reconfiguration message to the terminal device.
  • This RRC reconfiguration message may include configuration information for candidate cells. There may be one or more candidate cells.
  • the terminal device can store the configuration information of the candidate cells from the RRC reconfiguration message.
  • step S608 the terminal device sends an RRC reconfiguration complete message to the network device.
  • step S610 the terminal device and the candidate cell perform uplink synchronization and/or downlink synchronization.
  • the terminal device can perform uplink synchronization and/or downlink synchronization with the candidate cell in advance to reduce the interruption latency of the handover process.
  • the terminal device sends a measurement report to the network device.
  • This measurement report may be based on L1 measurements; that is, it is an L1 measurement report.
  • the measurement report may include measurement results for one or more candidate cells.
  • step S614 the network device makes an LTM decision. If the network device determines that the terminal device can perform an LTM handover, it proceeds to step S616. In some embodiments, the network device may determine a target cell based on the measurement results reported by the terminal device and instruct the terminal device to hand over to the target cell. In some embodiments, the network device may instruct the terminal device to hand over to the target cell via MAC CE.
  • step S616 the network device sends a cell switch command to the terminal device.
  • This cell switch command can be carried in the MAC CE.
  • step S618 the terminal device leaves the serving cell and initiates a random access procedure to the target cell.
  • the terminal device can use the configuration information of the target cell to initiate a random access procedure to the target cell. If the terminal device does not have a valid TA for the target cell, the terminal device can initiate a random access procedure to the target cell after receiving a cell handover command sent by the network device. If the terminal device has a TA for the target cell, the terminal device may not need to execute step S618.
  • step S620 the terminal device and the network device complete the LTM handover process.
  • the L1/L2 handover procedure places a significant amount of preparatory work before the handover time.
  • the terminal device can utilize the previously acquired TA and uplink resources to send uplink data to the target cell. Therefore, the time from "meeting the handover conditions" to "handover completion" is shortened, thereby reducing handover latency.
  • the LTM handover involved in the embodiments of this application can be a cell handover within the same CU or a cell handover across CUs; the embodiments of this application do not specifically limit this. It is understood that a network device may include one or more CUs, a CU may include one or more DUs, and a DU may include one or more cells.
  • Figure 7 illustrates several cell handover scenarios.
  • both the source and target cells belong to the same DU and the same CU; this handover method is called intra-DU cell handover.
  • the source and target cells belong to different DUs but to the same CU; this handover method is called intra-CU cell handover.
  • the source and target cells belong to different DUs and to different CUs; this handover method is called cross-CU cell handover.
  • the interaction flow shown in Figure 8 is described from the perspective of the terminal device, the source DU, the candidate DU, and the CU.
  • the source DU is the DU corresponding to the source cell
  • the candidate DU is the DU corresponding to the candidate cell
  • the source DU and the candidate DU belong to the same CU.
  • the terminal device can transmit user data with the source DU, and the source DU and CU can transmit user data.
  • the terminal device can perform L3 measurement and report the L3 measurement report.
  • the terminal device can send the L3 measurement report to the source cell, and the source cell can forward the L3 measurement report to the CU.
  • step S804 the CU can make an LTM configuration decision.
  • the CU can determine whether to allow the terminal device to perform an LTM handover based on the L3 measurement report. If the CU decides that the terminal device can perform an LTM handover, then proceed to step S806.
  • step S806 the CU sends a UE context setup request message to the candidate DU.
  • the UE context setup request message can be used to request configuration information of candidate cells within the coverage area of the candidate DU.
  • the candidate DU sends a UE context setup response message to the CU.
  • the UE context setup response message may include the candidate cell's configuration information.
  • the candidate cell's configuration information includes configuration information for LTM handover, such as time-domain resources, frequency-domain resources, C-RNTI, L1 measurement resources, L1 measurement reporting resources, and early TA configuration required for the terminal device to handover to the candidate cell.
  • step S810 the CU sends a UE context modification request message to the source DU.
  • the UE context modification request message is used to request the configuration information of candidate cells within the coverage area of the source DU.
  • the CU can carry the configuration information of the candidate cells within the coverage area of the DU in the UE context modification request message, that is, the CU can send the configuration information of the candidate cells within the coverage area of the DU to the source DU.
  • the source DU sends a UE context modification response message to the CU.
  • the UE context modification response message may include configuration information for the candidate cell.
  • This configuration information includes information for LTM handover, such as time-domain resources, frequency-domain resources, C-RNTI, L1 measurement resources, L1 measurement reporting resources, and early TA configuration required for the terminal device to handover to the candidate cell.
  • the CU can send the configuration information of candidate cells within the coverage area of the source DU to the candidate DU through step S814. If the CU does not obtain the configuration information of candidate cells within the coverage area of the source DU through step S812, the CU may not execute steps S814 and S816.
  • step S814 the CU sends a UE context modification request message to the candidate DU.
  • the UE context modification request message may include configuration information of candidate cells within the coverage area of the source DU.
  • step S816 the candidate DU sends a UE context modification response message to the CU.
  • step S818 the CU sends a downlink (DL) RRC message transfer message to the source DU.
  • This downlink RRC message transfer message may include an RRC reconfiguration message.
  • the RRC reconfiguration message may include configuration information for candidate cells used for LTM handover.
  • step S820 the source DU sends an RRC reconfiguration message to the terminal device.
  • the source DU can send the RRC reconfiguration message to the terminal device via transparent transmission.
  • step S822 after receiving the RRC reconfiguration message, the terminal device can send an RRC reconfiguration complete message to the source DU.
  • step S824 the source DU sends an uplink RRC message transfer (UL RRC message transfer) message to the CU.
  • This uplink RRC message transfer message may include an RRC reconfiguration complete message.
  • step S826 the terminal device and the candidate cell perform an early TA acquisition process.
  • the source DU sends an early TA acquisition command to the terminal device.
  • the terminal device can send a preamble to the candidate DU (or candidate cell).
  • the candidate DU can determine the TA based on the preamble.
  • the early TA acquisition command can be the PDCCH command (order).
  • step S828 after the candidate DU obtains the TA, it can send a DU-CU TA information transfer message to the CU.
  • This DU-CU TA information transfer message may include the TA of the candidate cell.
  • step S830 the CU sends a CU-DU TA information transfer message to the source DU.
  • This CU-DU TA information transfer message includes the TA of the candidate cell.
  • step S832 the terminal device performs an L1 measurement and sends an L1 measurement report to the source DU.
  • step S834 the source DU makes an LTM cell switch decision based on the L1 measurement report, that is, the source DU determines whether the terminal device should perform an LTM switch.
  • step S836 if the source DU determines that the terminal device can perform an LTM handover, the source DU sends a cell handover command to the terminal device.
  • This cell handover command includes the TA (Translation Address) of the candidate cell, enabling the terminal device to access the candidate cell based on that TA.
  • TA Translation Address
  • the candidate cell here can also be understood as the target cell.
  • step S838 the source DU sends a DU-CU cell switch notification to the CU.
  • the DU-CU cell switch notification may include the target cell ID and the transmission configuration indication (TCI) state ID.
  • step S840 if the target cell is a candidate DU, the CU sends a CU-DU cell switch notification to the candidate DU.
  • the CU-DU cell switch notification includes the identifier of the target cell and the TCI status identifier.
  • the source DU can also indicate the downlink data delivery status to the CU.
  • step S842 the candidate DU detection terminal device is accessed.
  • step S844 if the candidate DU detects that the terminal device has accessed the target cell, the candidate DU can send an access success message to the CU.
  • the access success message may include the ID of the target cell.
  • step S846 after the terminal device accesses the target cell, the terminal device can send an RRC reconfiguration complete message to the candidate DU.
  • step S848 the candidate DU sends an uplink RRC message transfer message to the CU, which may include an RRC reconfiguration complete message.
  • step S850 the CU sends a UE context release command to the source DU.
  • This UE context release command can be used to instruct the source DU to release the candidate cells that were prepared previously.
  • step S852 the source DU sends a UE context release complete message to the CU.
  • the terminal device After the terminal device accesses the target cell, the terminal device can transmit user data with the candidate DU, and the candidate DU can transmit user data with the CU.
  • the terminal device after the terminal device sends the preamble to the candidate cell, it does not need to wait for the RAR sent by the candidate cell or the serving cell.
  • the random access process can end after the terminal device sends the preamble to the candidate cell.
  • the serving cell sends a random access preamble assignment (RA preamble) to the terminal device.
  • the random access preamble assignment may contain configuration information for the preamble.
  • step S920 the terminal device sends a preamble to the candidate cell based on the random access preamble configuration. After the terminal device sends the preamble to the candidate cell, the random access procedure is completed, and the terminal device does not need to listen to the RAR.
  • the candidate cell can send the TA to the serving cell, and the serving cell will then send the TA to the terminal device via a cell handover command.
  • Figures 6 and 8 illustrate the cell handover process using cell handover within the same CU as an example.
  • the embodiments of this application are not limited to this.
  • Cell handover in the embodiments of this application can also be cell handover across CUs, that is, the source cell and the target cell belong to different CUs.
  • conditional handover For the conditional handover (CHO) mechanism, network devices can configure one or more candidate cells, along with the conditional handover events associated with those candidate cells, to the terminal device. These conditional handover events can also be called conditional handover trigger conditions. Accordingly, the terminal device can determine whether the conditional handover event is met based on the signal measurement results of the serving cell and/or the candidate cells. If the terminal device determines that a candidate cell meets the conditional handover event, it can initiate random access to that candidate cell.
  • conditional handover CHO
  • network devices can configure one or more candidate cells, along with the conditional handover events associated with those candidate cells, to the terminal device. These conditional handover events can also be called conditional handover trigger conditions. Accordingly, the terminal device can determine whether the conditional handover event is met based on the signal measurement results of the serving cell and/or the candidate cells. If the terminal device determines that a candidate cell meets the conditional handover event, it can initiate random access to that candidate cell.
  • condition switching event may include at least one of condition event A3, condition event A4, condition event A5, condition event D1, and condition event T1.
  • Conditional event A3 includes a candidate cell measurement result higher than the current serving cell measurement result of the terminal device, and the difference between the candidate cell measurement result and the current serving cell measurement result is greater than or equal to a first threshold.
  • Conditional event A4 includes a candidate cell measurement result that is greater than or equal to a second threshold.
  • Conditional event A5 includes situations where the measurement result of the current serving cell where the terminal device is located is lower than the third threshold, and the measurement result of the candidate cell is higher than the fourth threshold.
  • Conditional event D1 includes the fact that the distance between the terminal device and location reference point 1 is greater than the fifth threshold, and the distance between the terminal device and location reference point 2 is less than the sixth threshold.
  • Conditional event T1 includes the terminal device’s local time exceeding the configured time 1 but not exceeding the configured time 2, where time 2 is later than time 1.
  • condition events A3 and A5 can be applied to all types of conditional handover.
  • Condition events A4, D1, and T1 can be applied to non-terrestrial network (NTN) communication scenarios.
  • conditional handover can be configured with one or two conditional handover events.
  • condition events D1 and T1 need to be configured together with at least one of the other events (such as condition events A3, A4, and A5). If two conditional handover events are configured, the candidate cell will only trigger the random access procedure of the terminal device when both conditional handover events are met simultaneously.
  • condition switching event in this application embodiment can also be referred to as "condition switching trigger condition” or "condition switching related switching condition”.
  • conditional LTM handover the source DU does not need to send a handover command to the terminal device. Instead, the terminal device determines whether to perform a cell handover and which candidate cell to hand over to based on the conditional handover event. If the candidate cell meets the conditional handover event, the terminal device directly hands over to the candidate cell.
  • Conditional LTM handover can be configured with up to 8 candidate cells. These 8 candidate cells can be candidate cells within the same CU or candidate cells across CUs. This application embodiment does not specifically limit this.
  • the terminal device obtains the TA for the candidate cell through the handover command.
  • the source DU does not send a handover command to the terminal device. In this case, there is currently no clear solution on how the terminal device should obtain the TA for the candidate cell.
  • a large RAR response window (or RAR waiting window) needs to be set. Listening within the RAR response window for an extended period will result in significant energy consumption. The reasons for the large RAR response window are analyzed below.
  • the candidate cell obtains the TA (Transfer Aspect) through measurement and sends the TA to the serving cell.
  • the serving cell then sends the candidate cell's TA to the terminal device in the RAR (Range Array Receipt) manner.
  • the terminal device starts listening for the RAR three subframes after the subframe that sent the preamble.
  • the candidate cell and the serving cell belong to different CUs, there is a communication delay (e.g., 20ms) between the candidate cell and the serving cell. This results in a longer listening time for the terminal device to listen to the RAR, i.e., a larger RAR response time window, as shown in Figure 10. This causes the terminal device to consume a lot of energy by listening to the RAR response window for a long time.
  • a communication delay e.g. 20ms
  • embodiments of this application provide a wireless communication method and apparatus that enables a terminal device to explicitly obtain the TA (Target Acquisition Parameter) of a candidate cell.
  • a network device can send first information related to the reception parameters of the first TA (i.e., the TA of the candidate cell) to the terminal device. Based on the first information, the terminal device can determine the reception parameters of the first TA and use these parameters to receive the first TA. Therefore, the solution of this application embodiment enables the terminal device to obtain the first TA of a candidate cell through the reception parameters of the first TA.
  • the wireless communication method provided in the embodiments of this application will be described in detail below with reference to Figure 11.
  • the method shown in Figure 11 is described from the perspective of device interaction.
  • the specific form and number of each device shown are merely examples and should not constitute any limitation on the implementation of the method provided in this application.
  • the communication method of the embodiments of this application will be described in detail below using network devices and terminal devices as the main implementers.
  • the terminal device in the embodiments of this application can be the terminal device itself, or a chip, chip system, or processor that supports the terminal device in implementing communication methods, or a logic module or software that can implement all or part of the terminal device.
  • the network device in the embodiments of this application can be the network device itself, or a chip, chip system, or processor that supports the network device in implementing communication methods, or a logic module or software that can implement all or part of the network device.
  • the network device in this application can be a serving cell, a candidate cell, or a network element or network node to which the serving cell belongs.
  • the network device can be a CU or DU to which the serving cell belongs, or the network device can be a CU or DU to which the candidate cell belongs, etc.
  • step S1110 the network device sends first information to the terminal device.
  • the first information is used to determine the reception parameters of the first TA, wherein the first TA is the TA for the first candidate cell.
  • the first candidate cell is a cell that is different from the serving cell.
  • the first candidate cell is a cell adjacent to the serving cell; the first candidate cell can also be called a neighboring cell.
  • the first candidate cell can be any one of one or more candidate cells.
  • network devices can configure one or more candidate cells for terminal devices so that the terminal devices can perform uplink synchronization with one or more candidate cells in advance, thereby reducing the latency of cell handover.
  • the receiving parameters of the first TA can be understood as the receiving position of the first TA, the monitoring window of the first TA, the receiving window of the first TA, or the time-frequency position of the first TA, etc.
  • the receiving parameters of the first TA will be described in detail below.
  • step S1120 the terminal device receives the first TA based on the first information.
  • the first TA is determined by the first candidate cell.
  • the terminal device may send a preamble to the first candidate cell before receiving the first TA.
  • the first candidate cell can determine the first TA based on the preamble.
  • the network device can send configuration information of a first candidate cell to the terminal device.
  • This configuration information may include preamble configuration information.
  • the terminal device can determine the preamble to send to the first candidate cell.
  • the configuration information for the first candidate cell can be the early TA configuration for the first candidate cell.
  • the early TA configuration can include RACH configuration information.
  • the RACH configuration information can include preamble configuration information and preamble transmission resource information (such as time-domain resources, frequency-domain resources, etc.).
  • the early TA configuration can also be called the early UL synchronization configuration.
  • the network device can send a PDCCH order to the terminal device before the terminal device sends the preamble to the first candidate cell to trigger the early TA procedure. After receiving the PDCCH order from the network device, the terminal device can send the preamble to the first candidate cell.
  • the PDCCH order may include a random access preamble index, a synchronization signal (SS)/physical broadcast channel (PBCH) index, a PRACH mask index, etc.
  • SS synchronization signal
  • PBCH physical broadcast channel
  • the first TA can be sent from the serving cell to the terminal device.
  • the first candidate cell can determine the first TA.
  • the first candidate cell can then send the first TA to the serving cell, which in turn sends it to the terminal device.
  • the first TA can be sent from the first candidate cell to the terminal device.
  • the first candidate cell can determine the first TA.
  • the first candidate cell can send the first TA to the terminal device.
  • the first TA can be carried in a RAR. Carrying the first TA in a RAR allows the TA acquisition process to match the random access process, requiring minimal modification to the protocol and reducing communication complexity. As another example, the first TA can be carried in a MAC CE. Carrying the first TA in a MAC CE allows the terminal device to directly obtain the TA by receiving the MAC CE, without needing to listen in the RAR window, which helps reduce communication overhead and energy consumption.
  • the receiving parameters of the first TA may include the RAR response window and/or delay time.
  • the RAR response window is the window through which the terminal device listens to the RAR, and the terminal device can listen to the RAR carrying the first TA within the RAR response window.
  • the RAR response window can be a time period.
  • the RAR response window may include one or more of the following: a start position, an end position, and a window length.
  • the window length can reuse ra-ResponseWindowSize from related technologies, or it can be a newly defined window length; this application does not specifically limit this.
  • the RAR response window can be [T1, T2], where T1 is the start position of the RAR response window, T2 is the end position, and T2-T1 is the duration of the RAR response window.
  • the length of the RAR response window corresponding to different candidate cells can be the same or different; this application does not specifically limit this.
  • the RAR response window can also be called the RAR window (ra-response window), RAR listener window, RAR receive window, or RAR send window, etc.
  • the delay time can refer to the time interval between the start position of the RAR response window and the preamble transmission position. In other implementations, the delay time can be called the RAR delay time, or the RAR window opening delay time, etc. In still other implementations, the delay time can refer to the time interval between the start position of the RAR response window and the preamble transmission position + 3 subframes.
  • the terminal device does not open the RAR reply window and can continue to communicate with the serving cell, such as transmitting data with the serving cell.
  • the terminal device opens the RAR reply window and listens for the RAR carrying the TA (Telematics Acknowledgment).
  • the terminal device can open the RAR response time window after the delay time.
  • data transmission can be carried out based on the serving cell, thereby reducing the duration of RAR listening and helping to reduce the power consumption of the terminal device.
  • the unit of delay time can be any of milliseconds (ms), time slots, or subframes. In some implementations, the delay time can be 0, 3 subframes, 20ms, or 20ms + 3 subframes, etc.
  • the terminal device can open the RAR reply window after the delay time has elapsed following the transmission of the preamble. For example, the terminal device can maintain a timer corresponding to the delay time. After transmitting the preamble, the terminal device can start a timer of equal value to the delay time, and open the RAR reply window after the timer expires. Taking a delay time of 20ms as an example, the terminal device will open the RAR reply window 20ms after transmitting the preamble.
  • the delay time can be replaced by a time interval or a timer, etc.
  • the timer in the embodiments of this application can also be called a timer.
  • the terminal device receives the RAR within the RAR response window. After receiving the RAR carrying the first TA, the terminal device can stop the random access procedure.
  • the MAC CE can be an existing MAC CE or a newly defined MAC CE.
  • a newly defined MAC CE can also be called a dedicated MAC CE.
  • This MAC CE may include identification information of the first candidate cell, allowing the terminal device to clearly identify which candidate cell the TA carried in the MAC CE is for.
  • the MAC CE may include indication information indicating whether LTM is applied. This indication information is used to indicate whether the TI field in the MAC CE carries identification information of a candidate cell.
  • the TI field in the MAC CE carries the identification information of the first candidate cell; if the indication information indicates that the MAC CE is not applied to LTM, then the TI field in the MAC CE carries TAG ID information.
  • the identification information of the first candidate cell may include a candidate configuration ID and/or a candidate ID.
  • the candidate ID may be the physical cell identity (PCI) of the candidate cell.
  • This application embodiment does not specifically limit the fields carrying the identification information of the first candidate cell.
  • the identification information of the first candidate cell is carried in the TI field of the MAC CE, as shown in Figure 13a.
  • This application embodiment can indicate that the TA in the MAC CE is for the candidate cell by assigning a specific value to the TI field. Taking Figure 13a as an example, when the value of the TI field is 111, it indicates that the TA in the MAC CE is for the first candidate cell. Different values of the TI field can correspond to different candidate cells to distinguish candidate cells.
  • the identification information of the first candidate cell is carried in the R field of the MAC CE, as shown in Figure 13b.
  • a specific value is assigned to the R field to indicate that the TA in the MAC CE is the TA for the candidate cell.
  • Different values of the R field can correspond to different candidate cells, thus distinguishing between candidate cells.
  • the indication of whether it applies to LTM can be carried in the R field of MAC CE.
  • the L1 field in the MAC CE is used to indicate whether the timing advance command is used for a candidate cell. For example, if the L1 field (with a value of 1) indicates that the timing advance command is used for a candidate cell, then the following three fields (the field containing the candidate configuration index) indicate the candidate cell or include the candidate cell's identification information. If the L1 field indicates that the timing advance command is not used for a candidate cell, then the L1 field is the reserved bit R, which is set to 0.
  • the first information may include first configuration information, which includes TA (Transmission Terminal) reception parameters corresponding to one or more cells.
  • the first configuration information may include one or more TA reception parameters.
  • the one or more cells may include first candidate cells; that is, the first configuration information may include TA reception parameters corresponding to the first candidate cells, or the one or more TA reception parameters may include reception parameters for the first TA.
  • the terminal device may determine the reception parameters for the first TA based on the first configuration information; the terminal device may receive the first TA based on the reception parameters for the first TA.
  • This application embodiment can reduce the complexity of the terminal device determining the first TA reception parameter by configuring the TA reception parameters corresponding to the cell for the terminal device. Furthermore, the first configuration information can be used to configure TA reception parameters corresponding to multiple cells for the terminal device, meaning that TA reception parameters for multiple cells can be configured for the terminal device at once, reducing signaling overhead.
  • the TA (Transmission Response) parameters for different cells can be the same or different; this application does not specifically limit this.
  • the delay duration for cells belonging to the same network unit can be the same, while the delay duration for cells belonging to different network units can be different.
  • the network unit can be a CU (Cellular Unit).
  • the first configuration information may include TA receiving parameters corresponding to one or more network units.
  • the first configuration information may include TA receiving parameter A corresponding to network unit 1, receiving parameter B corresponding to network unit 2, and so on.
  • the TA receiving parameters corresponding to different network units may be the same or different, and this application embodiment does not specifically limit this.
  • network unit 1 and network unit 3 correspond to TA receiving parameter A
  • network unit 2 and network unit 4 correspond to TA receiving parameter B.
  • the first configuration information may include TA (Transmission Parameter) receiving parameters corresponding to the same network unit and/or TA receiving parameters corresponding to different network units.
  • the same network unit indicates that the candidate cell and the serving cell belong to the same network unit, while different network units indicate that the candidate cell and the serving cell belong to different network units.
  • the first configuration information may include the delay time corresponding to the same CU (e.g., timer1) and/or the delay time corresponding to different CUs (e.g., timer2).
  • the first configuration information may include a first identifier and TA receiving parameters corresponding to the first identifier.
  • the terminal device may determine the receiving parameters of the first TA based on the first identifier and the TA receiving parameters related to the first identifier; or it may determine the receiving parameters of the first TA based on the relationship between the first identifier corresponding to the source cell and the first identifier corresponding to the target cell, and the TA receiving parameters corresponding to the relationship.
  • This application embodiment configures a first identifier and corresponding TA receiving parameters for the terminal device, enabling the terminal device to determine the correspondence between the first identifier and the TA receiving parameters. This allows the terminal device to determine the receiving parameters of the first TA based on this correspondence. This reduces the complexity of the terminal device determining the TA receiving parameters.
  • the embodiments of this application do not specifically limit the content of the first identifier.
  • the specific content of the first identifier is described in detail below.
  • the first identifier can be an index (or identifier) of a TA receiving parameter.
  • the first configuration information includes one or more TA receiving parameters and the index corresponding to each TA receiving parameter.
  • the index of the TA receiving parameter can be determined based on the position of the TA receiving parameter in the first configuration information. Table 1 shows a correspondence between TA receiving parameters and their corresponding indices.
  • the first configuration information shown in Table 1 includes three TA receiving parameters, where the index of TA receiving parameter 0 is 0, the index of TA receiving parameter 1 is 1, and the index of TA receiving parameter 2 is 2.
  • the first identifier can be the identifier of a candidate cell, which can be the candidate cell ID, the candidate cell configuration ID, or the candidate cell index, etc.
  • the first configuration information includes the identifier of the candidate cell and the TA reception parameters corresponding to the identifier of the candidate cell; or, in other words, the first configuration information includes TA configuration parameters corresponding to one or more candidate cells.
  • Table 2 shows a correspondence between TA reception parameters and candidate cell identifiers.
  • candidate cell 0 corresponds to TA configuration parameter 1
  • candidate cell 1 corresponds to TA configuration parameter 1
  • candidate cell 2 corresponds to TA configuration parameter 2. If the first candidate cell is candidate cell 0, the terminal device can use TA reception parameter 0 to receive the first TA; if the first candidate cell is candidate cell 1, the terminal device can use TA reception parameter 1 to receive the first TA; if the first candidate cell is candidate cell 2, the terminal device can use TA reception parameter 2 to receive the first TA.
  • multiple candidate cells may correspond to the same TA (Transmission Parameter) receiving parameter.
  • candidate cell 0 and candidate cell 1 both correspond to TA receiving parameter 0.
  • the identifier of a candidate cell can be configured by the network device for the candidate cell.
  • the network device can assign identifiers to candidate cells within its coverage area.
  • the identifier assigned by the network device to the candidate cell can be 0, 1, 2, 3, ...
  • the first identifier can be the identifier of the network unit to which the candidate cell belongs. This embodiment determines the first identifier based on the network unit, which can reduce the number of TA (Transmission Access Parameters) parameters that need to be configured for the terminal device, thereby reducing resource overhead.
  • a network unit can also be called a network node.
  • This network unit can be, for example, a CU (Complex Unit).
  • the first configuration information can include the identifier of the CU and the TA reception parameters corresponding to the CU's identifier; or, the first configuration information can include TA reception parameters corresponding to one or more CUs. Table 3 shows a correspondence between TA reception parameters and network units.
  • network unit 0 corresponds to TA configuration parameter 1
  • network unit 1 corresponds to TA configuration parameter 1
  • network unit 2 corresponds to TA configuration parameter 2. If the first candidate cell belongs to network unit 0, the terminal device can use TA reception parameter 0 to receive the first TA; if the first candidate cell belongs to network unit 1, the terminal device can use TA reception parameter 1 to receive the first TA; if the first candidate cell belongs to network unit 2, the terminal device can use TA reception parameter 2 to receive the first TA.
  • multiple network units may correspond to the same TA receiving parameter.
  • network unit 0 and network unit 1 both correspond to TA receiving parameter 0.
  • the identifier of a network unit can be represented by a set ID. Assuming network unit 0 corresponds to set ID 0, network unit 1 corresponds to set ID 1, and network unit 2 corresponds to set ID 2, the correspondence shown in Table 3 can be transformed into Table 4.
  • the first configuration information may include one or more TA receive parameters corresponding to set IDs.
  • set ID0 corresponds to TA configuration parameter 0
  • set ID1 corresponds to TA configuration parameter 1
  • set ID2 corresponds to TA configuration parameter 2. If the set ID corresponding to the first candidate cell is set ID0, the terminal device can use TA reception parameter 0 to receive the first TA; if the set ID corresponding to the first candidate cell is set ID1, the terminal device can use TA reception parameter 1 to receive the first TA; and if the set ID corresponding to the first candidate cell is set ID2, the terminal device can use TA reception parameter 2 to receive the first TA.
  • the set ID in this application embodiment can also be replaced with no reset ID.
  • the first identifier can be an identifier indicating whether the candidate cell and the serving cell belong to the same network element. This application embodiment determines the first identifier based on the network element, which can reduce the number of TA (Transmission Acquisition) parameters that need to be configured for the terminal device, thereby reducing resource overhead.
  • TA Transmission Acquisition
  • the first configuration information may include TA (Transmission Acquisition) parameters corresponding to the same network element and/or TA parameters corresponding to different network elements.
  • TA Transmission Acquisition
  • a candidate cell belonging to the same CU as the serving cell can be called a "same CU”
  • a candidate cell belonging to a different CU than the serving cell can be called a "cross-CU.”
  • the first identifier may include the identifier of the same CU and/or the identifier of the cross-CU.
  • the first configuration information may include TA parameters corresponding to the same CU and/or TA parameters corresponding to the cross-CU. Table 5 shows a correspondence between the same network element, different network elements, and TA parameters.
  • the terminal device can use TA reception parameter 0 to receive the first TA; if the first candidate cell and the serving cell belong to different network units, the terminal device can use TA reception parameter 1 to receive the first TA.
  • Table 5 is only an example of using the identifier "0" to represent the same network unit and the identifier "1" to represent different network units, and the embodiments of this application are not limited thereto.
  • the embodiments of this application may also use the identifier "0" to represent different network units and the identifier "1" to represent the same network unit, or other identifier information may be used to represent the same network unit and different network units.
  • the "identifier of whether network elements are the same" shown in Table 5 can also be replaced with the "identifier of whether set IDs are the same".
  • Table 5 can be adjusted to the correspondence shown in Table 6 below.
  • the first configuration information may include TA receiving parameters corresponding to the same set ID and/or TA receiving parameters corresponding to different set IDs.
  • the terminal device can use TA receiving parameter 0 to receive the first TA; if the set IDs corresponding to the first candidate cell and the serving cell are different, the terminal device can use TA receiving parameter 1 to receive the first TA.
  • Table 6 is only an example of using the identifier "0" to represent the same set ID and the identifier "1" to represent different set IDs to illustrate the embodiments of this application.
  • the embodiments of this application are not limited to this.
  • the embodiments of this application may also use the identifier "0" to represent different set IDs and the identifier "1" to represent the same set ID, or other identifier information may be used to represent the same set ID and different set IDs.
  • the network device may also send first indication information to the terminal device.
  • This first indication information indicates a first identifier corresponding to the reception parameters of the first TA.
  • the terminal device can determine the reception parameters of the first TA based on the first indication information and the first configuration information.
  • the terminal device can determine the reception parameters of the first TA based on the first indication message and the TA reception parameters corresponding to the first identifier.
  • the network device can send the first indication message to the terminal device only when it needs the terminal device to receive the first TA. This allows the terminal device to receive the TA according to actual needs, avoiding invalid reception and wasting communication resources.
  • the first indication information can be carried in a PDCCH order.
  • a network device can send a PDCCH order to an end device to trigger an early TA procedure, and carry the first indication information in the PDCCH order.
  • the first indication information can indicate the index of the TA receiving parameters. For example, if the first indication information indicates that the index of the TA receiving parameters is index 1, then the terminal device can determine that the receiving parameter of the first TA is TA receiving parameter 1.
  • the first indication information can indicate the identifier of the first candidate cell. For example, if the identifier of the candidate cell in the first indication information is identifier 2, then the terminal device can determine that the reception parameter of the first TA is TA reception parameter 2.
  • the first indication information can indicate the identifier of the network element to which the first candidate cell belongs. For example, if the identifier of the network element indicated by the first indication information is identifier 2, then the terminal device can determine that the receiving parameter of the first TA is TA receiving parameter 2.
  • the first indication information can indicate the set ID corresponding to the first candidate cell. For example, if the first indication information indicates that the set ID corresponding to the first candidate cell is set ID0, then the terminal device can determine that the receiving parameter of the first TA is TA receiving parameter 0.
  • the first indication information can indicate whether the network element to which the first candidate cell and the serving cell belong is the same. For example, if the flag indicating whether the network elements are the same is 0, that is, the first indication information indicates that the first candidate cell and the serving cell belong to the same network element, then the terminal device can determine that the receiving parameter of the first TA is TA receiving parameter 0.
  • the first indication information can indicate whether the set IDs corresponding to the first candidate cell and the serving cell are the same. For example, if the flag indicating whether the set IDs are the same is 0, that is, if the first indication information indicates that the set IDs corresponding to the first candidate cell and the serving cell are different, then the terminal device can determine that the receiving parameter of the first TA is TA receiving parameter 0.
  • the first configuration information may include one or more TA (Transmission Acquisition) parameters, but not the first identifier.
  • the first configuration information includes a TA parameter that corresponds to a different network element. That is, when the first candidate cell and the serving cell belong to different network elements, the terminal device can use this TA parameter. If the first candidate cell and the serving cell belong to the same network element, the terminal device can use the default TA parameter.
  • the delay time included in the first configuration information can be 20ms, and the default delay time is 0. If the first candidate cell and the serving cell belong to the same network element, the terminal device can receive the first TA based on a delay time of 20ms. If the first candidate cell and the serving cell belong to the same network element, the terminal device can receive the first TA based on a delay time of 0ms.
  • the first indication information sent by the network device to the terminal device can indicate whether the network element to which the first candidate cell and the serving cell belong is the same. Based on the first indication information, the terminal device determines whether to receive the first TA based on the TA reception parameters in the first configuration information or based on the default TA reception parameters.
  • the first configuration information also includes a first identifier corresponding to the candidate cell.
  • the terminal device can determine the reception parameters of the first TA based on the first identifier corresponding to the candidate cell and the TA reception parameters corresponding to the first identifier.
  • the embodiments of this application can directly configure the first identifier corresponding to the candidate cell for the terminal device, so that the terminal device can determine the receiving parameters of the first TA on its own according to the first configuration information, without the need for additional instructions from the network device, thereby reducing signaling overhead.
  • the first configuration information also includes the identifier of the network element corresponding to the candidate cell; in other words, the first configuration information may include the correspondence between the identifiers of the candidate cell and the network element.
  • Table 7 shows one such correspondence between the identifiers of the candidate cell and the network element.
  • both cell 0 and cell 1 belong to network element 0, and cell 2 belongs to network element 2.
  • the terminal device can determine that the network element corresponding to the first candidate cell is network element 0. Based on network element 0 and the correspondence shown in Table 2, the terminal device can determine the receiving parameters of the first TA as TA receiving parameters 0.
  • the first configuration information also includes the identifier of the network element corresponding to the candidate cell; in other words, the first configuration information may include the correspondence between the identifiers of the candidate cell and the network element.
  • the first configuration information may include the correspondence shown in Table 7. The terminal device can determine whether the network elements corresponding to the candidate cell and the serving cell are the same based on the identifiers of the network elements corresponding to the candidate cell and the network element corresponding to the serving cell.
  • the terminal device can determine that the first candidate cell and the serving cell belong to the same network element, and the terminal device can determine the receiving parameter of the first candidate cell as TA receiving parameter 0 based on the correspondence shown in Table 5.
  • the terminal device can determine that the first candidate cell and the serving cell belong to different network units. Based on the correspondence shown in Table 5, the terminal device can determine the receiving parameter of the first candidate cell as TA receiving parameter 1.
  • the first configuration information also includes the set ID corresponding to the candidate cell; in other words, the first configuration information also includes the correspondence between candidate cells and set IDs.
  • the correspondence between candidate cells and set IDs can be shown in Table 8.
  • the set ID corresponding to the candidate cell can be the set ID corresponding to the early TA-related configuration of the candidate cell.
  • the set ID corresponding to cell 0 is set ID0
  • the set ID corresponding to cell 1 is set ID0
  • the set ID corresponding to cell 2 is set ID2. If the first candidate cell is cell 1, the terminal device can determine that the identifier corresponding to the first candidate cell is set ID0. Based on set ID0 and the correspondence shown in Table 4, the terminal device can determine that the receiving parameter of the first TA is TA receiving parameter 0.
  • the first configuration information may also include the set ID corresponding to the candidate cell, or in other words, the first configuration information may also include the correspondence between the candidate cell and the set ID.
  • the correspondence between the candidate cell and the set ID can be shown in Table 8. The terminal device can determine whether the set IDs corresponding to the first candidate cell and the serving cell are the same based on the set ID corresponding to the first candidate cell and the set ID corresponding to the serving cell.
  • the terminal device can determine that the set IDs corresponding to the first candidate cell and the serving cell are the same. Furthermore, based on the correspondence shown in Table 6, the terminal device can determine that the receiving parameter of the first candidate cell is TA receiving parameter 0.
  • the terminal device can determine that the set IDs corresponding to the first candidate cell and the serving cell are different. Furthermore, based on the correspondence shown in Table 6, the terminal device can determine that the receiving parameter of the first candidate cell is TA receiving parameter 1.
  • the network device needs to send the first configuration information to the terminal device to indicate the first identifier and the corresponding TA receiving parameters.
  • the network device can configure the first configuration information to the terminal device only once. Regardless of which cell the terminal device hands over to subsequently, the first configuration information can be used to determine the TA receiving parameters, thus saving signaling overhead.
  • the TA (Transmission Access Parameter) parameters corresponding to the first identifier may differ depending on the serving cell in which the terminal device is currently located. For example, for cells 1, 2, and 3, cells 1 and 2 belong to the same network unit, while cells 2 and 3 belong to different network units. Assume the terminal device switches from cell 1 to cell 2, then from cell 2 to cell 3, and then from cell 3 back to cell 1, and the first identifier is the identifier of the candidate cell. If the terminal device is currently serving in cell 1, since cells 1 and 2 belong to the same network unit, the TA reception parameter for cell 2 is reception parameter 1. Since cells 1 and 3 belong to different network units, the TA reception parameter for cell 3 is reception parameter 2.
  • the TA reception parameter for both cells 1 and 2 is reception parameter 2. Therefore, even within cell 2, the TA reception parameters for cell 2 will differ depending on the cell in which the terminal device is located (cells 1 and 3 are different).
  • the TA receiving parameter corresponding to network unit 1 is receiving parameter 1
  • the TA receiving parameter corresponding to network unit 2 is receiving parameter 2.
  • the serving cell of the terminal device is currently in cell 3
  • the TA receiving parameter corresponding to network unit 1 is receiving parameter 2
  • the TA receiving parameter corresponding to network unit 2 is receiving parameter 1.
  • the first configuration information may include configuration information for one or more cells, and the configuration information for each of the one or more cells includes the TA (Transmission Attack) parameters corresponding to that cell.
  • the terminal device can directly determine the first TA's reception parameters based on the configuration information of the one or more cells.
  • the correspondence between the TA receiving parameters and the cell can be implicitly included. This eliminates the need for additional configuration of the correspondence between the TA receiving parameters and the cell, which helps reduce transmission overhead.
  • the first configuration information may include the configuration information of cell 1, the configuration information of cell 2 and the configuration information of cell 3.
  • the configuration information of cell 1 includes the TA receiving parameters corresponding to cell 1
  • the configuration information of cell 2 includes the TA receiving parameters corresponding to cell 2
  • the configuration information of cell 3 includes the TA receiving parameters corresponding to cell 3.
  • the cell configuration information can be the cell's early TA configuration.
  • the terminal device can receive a first message sent by the network device before receiving the first TA. This first message triggers the terminal device to receive the first TA. In other words, the terminal device may not receive the first TA before receiving the first message, and may only receive the first TA after receiving the first message.
  • the terminal device is triggered to receive the first TA by the first message, which can avoid the terminal device receiving invalid TA and save the terminal device's power.
  • the network device can send the first message to the terminal device when the terminal device needs to receive the first TA, or after the network device receives the first TA sent by the first candidate cell. This avoids the terminal device receiving invalid TAs and helps save the terminal device's power.
  • the first message can be used to trigger the terminal device to open the RAR reply window, or the first message can be used to trigger the terminal device to start listening to the RAR.
  • the first message includes information about the first candidate cell, enabling the terminal device to clearly identify which candidate cell's TA (Transmission Acquisition) it needs to receive.
  • the first message may include the identification information and/or configuration information of the first candidate cell. If the terminal device has already sent preambles to multiple candidate cells before receiving the first TA, carrying the relevant information of the first candidate cell in the first message allows the terminal device to clearly identify which candidate cell's TA it needs to receive, thus achieving accurate TA reception.
  • the identification information of the first candidate cell can be any kind of information that can indicate the first candidate cell.
  • the identification information of the first candidate cell can be the candidate ID or the candidate configuration ID.
  • the configuration information of the first candidate cell can be the early TA configuration of the first candidate cell.
  • the network device before the terminal device sends the preamble to the first candidate cell, can send a second message to the terminal device.
  • This second message triggers the terminal device to send the preamble to the first candidate cell.
  • the second message could be a PDCCH order.
  • the terminal device After receiving the second message, the terminal device can then send the preamble to the first candidate cell.
  • the terminal device receives the first TA.
  • the second indication information is used to instruct the terminal device to receive the first TA. If the first TA is carried in a RAR, the second indication information can instruct the terminal device to open the RAR reply window.
  • Network devices can trigger terminal devices to receive the first TA by sending the same message to the terminal device (i.e., the first message and the second message are the same) or by directly carrying indication information in the first message. This method requires less modification to the protocol and can reduce the complexity of communication.
  • the first message is the same as the second message
  • the second message can mean that the first message and the second message carry the same content.
  • the preamble carried by the first message is the same as the preamble carried by the second message
  • the PDCCH order carried by the first message is the same as the PDCCH order carried by the second message.
  • the terminal device receives the first TA.
  • the network device can trigger the terminal device to receive the first TA using a first message that is identical to the second message. After receiving the second message, if the terminal device determines that the second message is identical to the first message, then the terminal device receives the first TA.
  • both the first and second messages are PDCCH orders.
  • the terminal device upon receiving the first message, can determine that the first message is used to trigger the terminal device to receive the first TA, and in response to the first message, the terminal device receives the first TA.
  • the terminal device receives a PDCCH order sent by the network device for the first time, the PDCCH order is used to trigger the terminal device to send a preamble to the first candidate cell, and the terminal device sends a preamble to the first candidate cell; if the terminal device receives the same PDCCH order again, the terminal device can determine that the PDCCH order is used to trigger the terminal device to receive the first TA, and in response to the PDCCH order, the terminal device receives the first TA.
  • the terminal device can determine that the first message is used to trigger the terminal device to receive the first TA, and in response to the first message, the terminal device receives the first TA. For example, if the terminal device receives a PDCCH order sent by the network device for the first time, this PDCCH order is used to trigger the terminal device to send a preamble to the first candidate cell.
  • the terminal device can determine that this PDCCH order is used to trigger the terminal device to receive the first TA, and in response to this PDCCH order, the terminal device receives the first TA.
  • the terminal device receives the first TA. If the terminal device receives the first message, and the first message contains second indication information, the terminal device receives the first TA.
  • the terminal device may ignore the first message; or the terminal device may ignore the RAR response window for the first candidate cell, that is, the terminal device does not listen to RAR within the RAR response window; or the terminal device may consider the first message as being used to trigger the terminal device to send a preamble to the first candidate cell. In this case, after receiving the first message, the terminal device may send a preamble to the first candidate cell.
  • the second indication information can occupy one bit, which reduces the resource overhead of the second indication information. For example, if the value of this bit is 0, it indicates that the first message is used to trigger the terminal device to receive the first TA.
  • the second message may include third indication information, which indicates that a first TA (Transmission Acquisition Message) will be received subsequently.
  • This third indication information distinguishes the process from the traditional TA acquisition process. If the second message received by the terminal device does not contain the third indication information, the terminal device can perform random access according to the traditional procedure (as shown in Figure 9). That is, after sending the preamble to the first candidate cell, the terminal device may not need to receive the first TA or listen to the RAR (Range Access Message). If the second message received by the terminal device contains the third indication information, the terminal device can wait for a subsequent second message from the network device to receive the first TA or listen to the RAR.
  • the second message contains third indication information
  • the first message contains the identification information of the first candidate cell and/or the configuration information of the first candidate cell.
  • the first and second messages are the same.
  • the first message and the second message are the same, and the first message contains the second instruction information.
  • the reception parameters of the first TA can be determined by the serving cell.
  • the serving cell can send the reception parameters of the first TA to the terminal device and/or the first candidate cell.
  • the terminal device can receive the first TA based on the reception parameters of the first TA, and the first candidate cell can send the first TA based on the reception parameters of the first TA. In this way, the serving cell, the first candidate cell, and the terminal device can maintain a consistent understanding of the reception parameters of the first TA, which is beneficial to ensuring the normal operation of communication.
  • the serving cell can also send information about the preamble to the first candidate cell, so that the first candidate cell can determine the reception parameters of the first TA based on the information about the preamble.
  • the reception parameters of the first TA can be the RAR reception window, specifically the time period [T1, T2] after the preamble is received.
  • the first candidate cell can determine the start time of the RAR reception window based on the information about the preamble.
  • the first candidate cell can send the first TA based on the transmission parameters of the first TA. Taking the reception parameters of the first TA as the RAR reception window as an example, the first candidate cell can send the first TA to the terminal device within the RAR reception window.
  • the reception parameters of the first TA can be determined by the first candidate cell.
  • the first candidate cell can send the reception parameters of the first TA to the serving cell, and the serving cell can send the reception parameters of the first TA to the terminal device. This method ensures that the serving cell, the first candidate cell, and the terminal device have a consistent understanding of the reception parameters of the first TA, which is beneficial for ensuring normal communication operation.
  • the serving cell determines the time period during which scheduling is not possible, thereby avoiding impacting the serving cell's scheduling of the terminal device.
  • the first candidate cell can send its configuration information (such as early TA configuration) to the serving cell, which can then forward this information to the terminal device.
  • the configuration information includes the receiving parameters for the first TA.
  • the first candidate cell can also send the receiving parameters for the first TA from its configuration information to the serving cell, allowing the serving cell to determine unschedulable time periods during which the terminal device will not be scheduled.
  • the network device can directly indicate the reception parameters of the first TA to the terminal device.
  • the first information includes fourth indication information, which is used to indicate the reception parameters of the first TA.
  • the network device can directly indicate a delay time to the terminal device, such as x ms or 10 ms. After receiving the fourth indication information, the terminal device can receive the first TA based on the delay time indicated by the fourth indication information.
  • the network device can directly indicate the reception parameters of the first TA to the terminal device, thereby reducing the complexity of obtaining the TA reception parameters. For example, if the network device receives a TA sent by a candidate cell, the network device can indicate the TA reception parameters for that candidate cell to the terminal device, and the terminal device can directly use the TA reception parameters to receive the TA.
  • the RAR response window in this application embodiment can be a periodic window.
  • the first information may include one or more of the following: the starting position of the periodic window, the number of periods, and the period length.
  • the terminal device can determine the position of the periodic window based on the first information.
  • the periodic window can be applied to multiple candidate cells, meaning that the TAs of multiple candidate cells can be transmitted within the periodic window.
  • the serving cell can send a RAR to the terminal device at the next window position (the nearest window position), and the RAR carries the first TA.
  • the first candidate cell can send a RAR to the terminal device at the next window position (the nearest window position) after determining the first TA, and the RAR carries the first TA.
  • the serving cell may not schedule the terminal device at the location of that periodic window.
  • the terminal device can listen for RAR at the location of the periodic window to obtain the first TA.
  • the terminal device can perform cell handover based on the first TA.
  • cell handover can be LTM handover or conditional LTM handover.
  • the terminal device can determine whether the first candidate cell meets the handover conditions based on the conditional handover event corresponding to the first candidate cell. If the first candidate cell meets the conditional handover event, the terminal device can hand over to the first candidate cell based on the first TA.
  • this application also provides a method for obtaining the first TA.
  • the network device can indicate the first TA to the terminal device via a MAC CE. In this way, the terminal device can obtain the first TA directly by receiving the MAC CE without needing to determine the TA's reception parameters.
  • step S1410 the terminal device receives a MAC CE sent by the network device.
  • This MAC CE includes the TA of the first candidate cell.
  • the terminal device Before the terminal device receives the MAC CE, it can send a preamble to the first candidate cell. After receiving the preamble, the first candidate cell can determine the first TA based on it. After determining the first TA, the first candidate cell can send the first TA to the serving cell, which can then carry the first TA in the MAC CE and send the MAC CE to the terminal device.
  • the MAC CE in this application embodiment can be an existing MAC CE or a newly defined MAC CE.
  • the newly defined MAC CE can also be called a dedicated MAC CE.
  • the MAC CE may include the identification information of the first candidate cell, so that the terminal device can clearly identify which candidate cell the TA carried in the MAC CE is for.
  • the identification information of the first candidate cell may include a candidate configuration ID and/or a candidate ID.
  • the candidate ID may be the physical cell identity (PCI) of the candidate cell.
  • This application embodiment does not specifically limit the fields carrying the identification information of the first candidate cell.
  • the identification information of the first candidate cell is carried in the TI field of the MAC CE, as shown in Figure 13a.
  • This application embodiment can indicate that the TA in the MAC CE is for the candidate cell by assigning a specific value to the TI field. Taking Figure 13a as an example, when the value of the TI field is 111, it indicates that the TA in the MAC CE is for the first candidate cell. Different values of the TI field can correspond to different candidate cells to distinguish candidate cells.
  • the identification information of the first candidate cell is carried in the R field of the MAC CE, as shown in Figure 13b.
  • a specific value is assigned to the R field to indicate that the TA in the MAC CE is the TA for the candidate cell.
  • Different values of the R field can correspond to different candidate cells, thus distinguishing between candidate cells.
  • the terminal device can perform conditional handover based on the first TA.
  • This conditional handover can be a conditional LTM handover.
  • Examples 1 to 9 illustrate the embodiments of this application by taking the TA receiving parameters as the delay time and the TA as the carrier in RAR.
  • the serving cell can send first configuration information to the terminal device.
  • This first configuration information may include a delay timer1 corresponding to a cross-CU and/or a delay timer2 corresponding to the same CU.
  • Timer1 can be 20ms and timer2 can be 0ms.
  • the serving cell sends a PDCCH order to the terminal device, which is used to trigger the early TA procedure.
  • This PDCCH order carries an indication of whether the operation crosses a CU or is within the same CU. Based on the delay times corresponding to cross-CU and same-CU operations, and the indications in the PDCCH order, the terminal device determines the delay time for this RAR.
  • the terminal device can start a timer with a delay equal to the RAR delay time. After the timer expires, the ra-ResponseWindow is opened. The terminal device receives the corresponding RAR within the ra-ResponseWindow and stops the random access procedure after receiving the RAR.
  • the serving cell can send first configuration information to the terminal device, which may include multiple delay times and their corresponding indexes.
  • the serving cell sends a PDCCH order to the terminal device, which triggers the early TA procedure.
  • This PDCCH order carries an index corresponding to the delay time. Based on multiple delay times, their corresponding indices, and the indications in the PDCCH order, the terminal device determines the delay time for this RAR.
  • the terminal device can start a timer with a delay equal to the RAR delay time. After the timer expires, the ra-ResponseWindow is opened. The terminal device receives the corresponding RAR within the ra-ResponseWindow and stops the random access procedure after receiving the RAR.
  • the serving cell sends a PDCCH order to the terminal device, which is used to trigger the early TA procedure.
  • the PDCCH order carries a delay time, such as x ms or 10ms.
  • the terminal device can start a timer with a delay equal to the RAR delay time. After the timer expires, the ra-ResponseWindow is opened. The terminal device receives the corresponding RAR within the ra-ResponseWindow and stops the random access procedure after receiving the RAR.
  • the serving cell sends a PDCCH order to the terminal device, which triggers the early access procedure (TA).
  • This PDCCH order includes indication information for subsequent RAR (Range Access Response) indications.
  • RAR Range Access Response
  • the PDCCH order in the conventional mechanism can be distinguished from the PDCCH order in this embodiment.
  • the random access procedure ends after the terminal device sends the preamble.
  • the serving cell instructs the terminal device to begin the RAR listening window.
  • the serving cell may send the same PDCCH order as the triggering preamble to the terminal device, or it may send a newly defined instruction.
  • the serving cell may send instruction information to the terminal device that indicates a first candidate cell or the configuration of the first candidate cell.
  • the serving cell can send information such as the preamble and the RAR reply window to the first candidate cell after sending the PDCCH order.
  • the RAR reply window can be a time period [T1, T2] after the preamble is received.
  • the first candidate cell sends a RAR to the terminal device within the RAR reply window.
  • the terminal device listens for the RAR from the first candidate cell at the corresponding listening position, which can be the time period [T1, T2] after the preamble is sent.
  • the terminal device After receiving the instruction from the network device, the terminal device opens the RAR reply window and receives the RAR carrying the first TA. Upon receiving the RAR, the terminal device stops the random access procedure.
  • the serving cell sends early TA-related configurations to the terminal device.
  • These early TA-related configurations may include the RAR delay time and the set ID corresponding to the candidate cell's early TA-related configuration.
  • the RAR delay time may include a delay time (timer1) corresponding to the same CU and a delay time (timer1) corresponding to different CUs.
  • the terminal device After sending the preamble to the first candidate cell, the terminal device can determine the required RAR delay time based on the delay time and set ID, and start a timer with a delay time equal to that RAR delay time. After the timer expires, the ra-ResponseWindow is opened. The terminal device receives the corresponding RAR within the ra-ResponseWindow, and stops the random access procedure after receiving the RAR.
  • the terminal device When the terminal device sends a preamble to the first candidate cell, it can determine the set ID of the first candidate cell and the set ID of the serving cell. If the set ID of the first candidate cell is the same as the set ID of the serving cell, it is within the same CU, and the terminal device uses timer1; if the set ID of the first candidate cell is different from the set ID of the serving cell, it is across CUs, and the terminal device uses timer2.
  • the serving cell sends early TA-related configurations to the terminal device.
  • These early TA-related configurations may include the RAR delay time and the set ID corresponding to the early TA-related configurations of the candidate cells.
  • the RAR delay time may include the delay time corresponding to one or more CUs.
  • CU1 set ID 1
  • CU2 set ID 2
  • CU3 set ID 3
  • CU4 set ID 4
  • the terminal device After sending the preamble to the first candidate cell, the terminal device can determine the required RAR delay time based on the delay time and set ID, and start a timer with a delay time equal to that RAR delay time. After the timer expires, the ra-ResponseWindow is opened. The terminal device receives the corresponding RAR within the ra-ResponseWindow, and stops the random access procedure after receiving the RAR.
  • Terminal devices can determine the RAR response window based on the early TA configuration corresponding to the candidate cell.
  • the candidate cell can send the RAR response window in the early TA configuration to the serving cell, which is used by the serving cell to determine the time period during which scheduling is not possible.
  • the terminal device After receiving the instruction from the network device to open the RAR listening window, the terminal device opens the RAR listening window to receive the RAR carrying the first TA sent by the first candidate cell. Upon receiving the RAR, the terminal device stops the random access procedure.
  • the serving cell sends first configuration information to the terminal device.
  • the first configuration information includes information related to the receiving location of the RAR of the TA carrying the candidate cell.
  • the RAR reception location can be a periodic location. This periodic location can be applied to multiple candidate cells. Location-related information can include the start location, period, and duration. The duration can be the same as the size of the RAR response window, or it can be a newly configured duration.
  • the serving cell After receiving a TA (Transaction Acquisition) from a candidate cell, the serving cell (or source cell) can periodically transmit a RAR (Record Animation) carrying that TA. After the terminal device sends a preamble, it can receive the RAR from the serving cell at those periodic locations.
  • TA Transaction Acquisition
  • RAR Record Animation
  • the terminal device, serving cell, and candidate cell can maintain a consistent understanding of the location of the RAR response window, which helps ensure normal communication and avoids impacting the scheduling of the serving cell.
  • the serving cell indicates the TA of the candidate cell to the terminal device through the MAC CE.
  • This MAC CE can be an existing MAC CE or a newly defined MAC CE.
  • the MAC CE needs to indicate whether the TA carried is the TA of the candidate cell and/or whether it is applied to LTM.
  • the candidate cell can be indicated by the TAG ID field in the MAC CE (as shown in Figure 13a), and/or whether it is applied to LTM can be indicated by the R field in the MAC CE (as shown in Figure 13b).
  • the MAC CE may include a candidate configuration ID.
  • Figure 15 is a schematic block diagram of a communication device provided in an embodiment of this application. As shown in Figure 15, the communication device 1500 includes a first receiving module 1510 and a second receiving module 1520.
  • the device 1500 can be used to perform the steps described above by the terminal device.
  • the first receiving module 1510 is used to receive first information sent by the network device.
  • the first information is used to determine the receiving parameters of the first timing advance TA.
  • the first TA is a TA for a first candidate cell, and the first candidate cell is a cell different from the serving cell.
  • the second receiving module 1520 is used to receive the first TA based on the first information.
  • the first information includes first configuration information, which includes TA receiving parameters corresponding to one or more cells, and the one or more cells include the first candidate cell; the device 1500 further includes a determining module, which is used to determine the receiving parameters of the first TA based on the first configuration information; and the second receiving module 1520 is used to receive the first TA based on the receiving parameters of the first TA.
  • the first configuration information includes a first identifier and TA receiving parameters corresponding to the first identifier, wherein the TA receiving parameters corresponding to the first identifier include the receiving parameters of the first TA.
  • the determining module is used to determine the receiving parameters of the first TA based on the first identifier corresponding to the first candidate cell and the TA receiving parameters corresponding to the first identifier.
  • the method further includes: receiving first indication information sent by the network device, the first indication information being used to indicate the first identifier corresponding to the receiving parameters of the first TA.
  • the first configuration information further includes the first identifier corresponding to the candidate cell
  • the determining module is used to determine the receiving parameters of the first TA based on the first identifier corresponding to the candidate cell and the TA receiving parameters corresponding to the first identifier.
  • the first identifier includes any one of the following: the identifier of the network unit to which the candidate cell belongs; or an identifier indicating whether the candidate cell and the serving cell belong to the same network unit.
  • the network unit is a CU.
  • the first identifier includes the index of the TA receive parameters and/or the identifier of the candidate cell.
  • the first configuration information includes configuration information of the one or more cells, and the configuration information of the one or more cells respectively includes TA receiving parameters corresponding to the one or more cells.
  • the cell's configuration information is the cell's early TA configuration.
  • the device 1500 before receiving the first TA, the device 1500 further includes a third receiving module for receiving a first message sent by the network device, the first message being used to trigger the terminal device to receive the first TA.
  • the first message includes the identification information of the first candidate cell and/or the configuration information of the first candidate cell.
  • the apparatus further includes a fourth receiving module: configured to receive a second message sent by the network device before the second receiving module 1520 receives the first TA, the second message being used to trigger the terminal device to send a preamble to the first candidate cell; the second receiving module 1520 is configured to: receive the first TA if the first message is the same as the second message and/or the first message contains second indication information, wherein the second indication information is used to instruct the terminal device to receive the first TA.
  • a fourth receiving module configured to receive a second message sent by the network device before the second receiving module 1520 receives the first TA, the second message being used to trigger the terminal device to send a preamble to the first candidate cell; the second receiving module 1520 is configured to: receive the first TA if the first message is the same as the second message and/or the first message contains second indication information, wherein the second indication information is used to instruct the terminal device to receive the first TA.
  • the second message includes third indication information, which indicates that there is a subsequent reception indication for the first TA.
  • both the first message and the second message are Physical Downlink Control Channel (PDCCH) commands.
  • PDCCH Physical Downlink Control Channel
  • the first information includes fourth indication information, which is used to indicate the receiving parameters of the first TA.
  • the reception parameters of the first TA are sent from the first candidate cell to the network device.
  • the first TA is carried in the Random Access Response (RAR) or the Media Access Control (MAC) control element (CE).
  • RAR Random Access Response
  • MAC Media Access Control
  • the first TA is carried in a RAR
  • the receiving parameters of the first TA include a RAR response window and/or a delay time.
  • the RAR response window is a window for listening to the RAR carrying the first TA
  • the delay time is the time interval between the start position of the RAR response window and the transmission position of the preamble.
  • the preamble is a preamble sent by the terminal device to the first candidate cell.
  • the receiving parameters of the first TA include the delay time and the length of the RAR reply window.
  • the receiving parameters of the first TA include one or more of the following: the start position of the RAR reply window, the window length, and the end position.
  • the RAR response window is a periodic window
  • the first information includes one or more of the following: the starting position of the periodic window, the number of periods, and the period length.
  • the MAC CE includes identification information of the first candidate cell and/or indication information on whether it is applied to LTM-based information.
  • the identification information of the first candidate cell is carried in the TI field of the MAC CE, and/or the indication information of whether it is applied to LTM is carried in the R field.
  • the second receiving module 1520 is used to: receive the first TA sent by the serving cell; or receive the first TA sent by the first candidate cell.
  • Figure 16 is a schematic block diagram of a communication device provided in an embodiment of this application. As shown in Figure 16, the communication device 1600 includes a transmitting module 1610.
  • the device 1600 can be used to perform the steps described above by the network device.
  • the sending module 1610 is used to send first information to the terminal device.
  • the first information is used to determine the receiving parameters of the first timing advance TA.
  • the first TA is a TA for a first candidate cell, and the first candidate cell is a cell different from the serving cell.
  • the first information includes first configuration information, which includes TA (Transmission Attack) reception parameters corresponding to one or more cells, wherein the one or more cells include the first candidate cell, and the reception parameters of the first TA are determined based on the first configuration information.
  • TA Transmission Attack
  • the first configuration information includes a first identifier and TA receiving parameters corresponding to the first identifier, wherein the TA receiving parameters corresponding to the first identifier include the receiving parameters of the first TA.
  • the sending module 1610 is further configured to: send first indication information to the terminal device, the first indication information being used to indicate the first identifier corresponding to the receiving parameters of the first TA.
  • the first configuration information further includes the first identifier corresponding to the candidate cell.
  • the first identifier corresponding to the candidate cell, and the TA receiving parameters corresponding to the first identifier, are used to determine the first TA.
  • the first identifier includes any one of the following: the identifier of the network unit to which the candidate cell belongs; or an identifier indicating whether the candidate cell and the serving cell belong to the same network unit.
  • the network unit is a CU.
  • the first identifier includes the index of the TA receive parameters and/or the identifier of the candidate cell.
  • the first configuration information includes configuration information of the one or more cells, and the configuration information of the one or more cells respectively includes TA receiving parameters corresponding to the one or more cells.
  • the cell's configuration information is the cell's early TA configuration.
  • the sending module 1610 is further configured to: send a first message to the terminal device, the first message being used to trigger the terminal device to receive the first TA.
  • the first message includes the identification information of the first candidate cell and/or the configuration information of the first candidate cell.
  • the sending module 1610 is further configured to: send a second message to the terminal device, the second message being used to trigger the terminal device to send a preamble to the first candidate cell; wherein the first message is the same as the second message, and/or the first message contains second indication information, the second indication information being used to instruct the terminal device to receive the first TA.
  • the second message includes third indication information, which indicates that there is a subsequent reception indication for the first TA.
  • both the first message and the second message are Physical Downlink Control Channel (PDCCH) commands.
  • PDCCH Physical Downlink Control Channel
  • the first information includes fourth indication information, which is used to indicate the receiving parameters of the first TA.
  • the reception parameters of the first TA are sent from the first candidate cell to the network device.
  • the first TA is carried in the Random Access Response (RAR) or the Media Access Control (MAC) control element (CE).
  • RAR Random Access Response
  • MAC Media Access Control
  • the first TA is carried in a RAR
  • the receiving parameters of the first TA include a RAR response window and/or a delay time.
  • the RAR response window is a window for listening to the RAR carrying the first TA
  • the delay time is the time interval between the start position of the RAR response window and the transmission position of the preamble.
  • the preamble is a preamble sent by the terminal device to the first candidate cell.
  • the receiving parameters of the first TA include the delay time and the length of the RAR reply window.
  • the receiving parameters of the first TA include one or more of the following: the start position of the RAR reply window, the window length, and the end position.
  • the RAR response window is a periodic window
  • the first information includes one or more of the following: the starting position of the periodic window, the number of periods, and the period length.
  • the MAC CE includes identification information of the first candidate cell and/or indication information on whether it is applied to LTM-based information.
  • the identification information of the first candidate cell is carried in the TI field of the MAC CE, and/or the indication information of whether it is applied to LTM is carried in the R field.
  • the apparatus 1600 further includes a receiving module for receiving the receiving parameters of the first TA sent by the first candidate cell; or the sending module 1610 is further used to send the receiving parameters of the first TA to the first candidate cell.
  • Figure 17 is a schematic block diagram of a communication device provided in an embodiment of this application. As shown in Figure 17, the communication device 1700 includes a receiving module 1710.
  • the device 1700 can be used to perform the steps described above by the terminal device.
  • the receiving module 1710 is used to receive a MAC CE sent by a network device, wherein the MAC CE includes a first TA for a first candidate cell, and the first candidate cell is a cell different from the serving cell.
  • the MAC CE includes identification information of the first candidate cell and/or indication information on whether it is applied to LTM-based information.
  • the identification information of the first candidate cell is carried in the TI field of the MAC CE, and/or the indication information of whether it is applied to LTM is carried in the R field.
  • the method further includes sending a preamble to the first candidate cell before receiving the MAC CE sent by the network device.
  • Figure 18 is a schematic block diagram of a communication device provided in an embodiment of this application. As shown in Figure 18, the communication device 1800 includes a transmitting module 1810.
  • the device 1800 can be used to perform the steps described above by the network device.
  • the sending module 1810 is used to send a MAC CE to the terminal device, wherein the MAC CE includes a first TA for a first candidate cell, and the first candidate cell is a cell different from the serving cell.
  • the MAC CE includes identification information of the first candidate cell and/or indication information on whether it is applied to LTM-based information.
  • the identification information of the first candidate cell is carried in the TI field of the MAC CE, and/or the indication information of whether it is applied to LTM is carried in the R field.
  • devices 1500-1800 are embodied in the form of functional modules.
  • the term "module” here can refer to an application-specific integrated circuit (ASIC), electronic circuitry, a processor (e.g., a shared processor, proprietary processor, or group processor, etc.) and memory for executing one or more software or firmware programs, integrated logic circuitry, and/or other suitable components supporting the described functions.
  • ASIC application-specific integrated circuit
  • devices 1500 and 1700 can be specifically defined as the terminal devices in the above embodiments, and devices 1500 and 1700 can be used to perform the various processes and/or steps corresponding to the terminal devices in the above method embodiments.
  • Devices 1600 and 1800 can be specifically defined as network devices in the above embodiments, and devices 1600 and 1800 can be used to perform the various processes and/or steps corresponding to the network devices in the above method embodiments. To avoid repetition, further details are omitted here.
  • the aforementioned devices 1500 and 1700 are functionally capable of implementing the corresponding steps performed by the terminal device in the aforementioned method, while devices 1600 and 1800 are functionally capable of implementing the corresponding steps performed by the network device in the aforementioned method.
  • These functions can be implemented in hardware or by hardware executing corresponding software.
  • the hardware or software includes one or more modules corresponding to the aforementioned functions.
  • devices 1500-1800 may also be chips, such as a system-on-chip (SOC) or a modem.
  • the receiving module and the transmitting module may be the transceiver circuits of the chip, and are not limited herein.
  • Figure 19 is a schematic structural diagram of a communication device according to an embodiment of this application.
  • the dashed lines in Figure 19 indicate that the unit or module is optional.
  • This device 1900 can be used to implement the methods described in the above method embodiments.
  • Device 1900 can be a chip, a terminal device, or a network device.
  • Apparatus 1900 may include one or more processors 1910.
  • the processor 1910 may support apparatus 1900 in implementing the methods described in the preceding method embodiments.
  • the processor 1910 may be a general-purpose processor or a special-purpose processor.
  • the processor may be a central processing unit (CPU).
  • the processor may be other general-purpose processors, digital signal processors (DSPs), ASICs, field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc.
  • the general-purpose processor may be a microprocessor or any conventional processor.
  • the apparatus 1900 may further include one or more memories 1920.
  • the memories 1920 store a program that can be executed by the processor 1910, causing the processor 1910 to perform the methods described in the preceding method embodiments.
  • the memories 1920 may be independent of the processor 1910 or integrated within the processor 1910.
  • the device 1900 may also include a transceiver 1930.
  • the processor 1910 can communicate with other devices or chips via the transceiver 1930.
  • the processor 1910 can send and receive data with other devices or chips via the transceiver 1930.
  • This application also provides a computer-readable storage medium for storing a program.
  • This computer-readable storage medium can be applied to a terminal device or network device provided in this application embodiment, and the program causes a computer to execute the methods performed by the terminal device or network device in the various embodiments of this application.
  • the application also provides a computer program product.
  • the computer program product includes a program.
  • This computer program product can be applied to a terminal device or network device provided in the embodiments of this application, and the program causes a computer to execute the methods performed by the terminal device or network device in the various embodiments of this application.
  • This application also provides a computer program.
  • This computer program can be applied to the terminal device or network device provided in this application, and the computer program causes the computer to execute the methods performed by the terminal device or network device in various embodiments of this application.
  • B corresponding to A means that B is associated with A, and B can be determined based on A.
  • determining B based on A does not mean that B is determined solely based on A; B can also be determined based on A and/or other information.
  • Entities A and B can be RAN nodes or terminals, or modules within RAN nodes or terminals. Information transmission and reception can be between RAN nodes and terminals, such as between a base station and a terminal; between two RAN nodes, such as between a CU and a DU; or between different modules within a single device, such as between a terminal chip and other modules of the terminal, or between a base station chip and other modules of the base station.
  • the disclosed systems, apparatuses, and methods can be implemented in other ways.
  • the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods.
  • multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed.
  • the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.
  • the units described as separate components may or may not be physically separate.
  • the components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.
  • the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.
  • implementation can be achieved entirely or partially through software, hardware, firmware, or any combination thereof.
  • software When implemented using software, it can be implemented entirely or partially in the form of a computer program product.
  • the computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated.
  • the computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device.
  • the computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another.
  • the computer instructions can be transmitted from one website, computer, server, or data center to another via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means.
  • the computer-readable storage medium can be any available medium that a computer can read or a data storage device such as a server or data center that integrates one or more available media.
  • the available media may be magnetic media (e.g., floppy disks, hard disks, magnetic tapes), optical media (e.g., digital video discs (DVDs)), or semiconductor media (e.g., solid-state drives (SSDs)).

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

La présente demande concerne un procédé de communication sans fil et un appareil de communication, qui fournissent une solution claire à un dispositif terminal pour acquérir une TA d'une cellule candidate. Le procédé consiste à : recevoir des premières informations envoyées par un dispositif de réseau, les premières informations étant utilisées pour déterminer un paramètre de réception pour une première avance temporelle (TA), la première TA étant une TA pour une première cellule candidate, et la première cellule candidate étant une cellule différente d'une cellule de desserte ; et, sur la base des premières informations, recevoir la première TA.
PCT/CN2025/094698 2024-07-24 2025-05-13 Procédé de communication sans fil et appareil de communication Pending WO2026020937A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CN202411012338.9A CN121463127A (zh) 2024-07-24 2024-07-24 无线通信方法及通信装置
CN202411012338.9 2024-07-24

Publications (1)

Publication Number Publication Date
WO2026020937A1 true WO2026020937A1 (fr) 2026-01-29

Family

ID=98564886

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2025/094698 Pending WO2026020937A1 (fr) 2024-07-24 2025-05-13 Procédé de communication sans fil et appareil de communication

Country Status (2)

Country Link
CN (1) CN121463127A (fr)
WO (1) WO2026020937A1 (fr)

Also Published As

Publication number Publication date
CN121463127A (zh) 2026-02-03

Similar Documents

Publication Publication Date Title
TWI676400B (zh) 一種進行隨機存取的方法和設備
US10064110B2 (en) Method and apparatus for handover in wireless communication system
US20200252958A1 (en) Data transmission method and device, search space optimization method and device, and storage medium
US20160262179A1 (en) Method for obtaining uplink synchronization and configuring uplink connection
CN110557837B (zh) 通信方法和装置
WO2019154272A1 (fr) Procédé de reprise sur défaillance de faisceau, et terminal d'utilisateur
KR20160034994A (ko) 데이터 전송 방법, 장치 및 시스템
US20250056597A1 (en) Information transmission method and communication apparatus
US20230049532A1 (en) Random access method and terminal device
US12513757B2 (en) Connection establishment method, apparatus, device, and storage medium
US20230292377A1 (en) Random access method and device
WO2022116839A1 (fr) Procédé et appareil de communication, dispositif, support de stockage et produit-programme
WO2024022511A1 (fr) Procédé et appareil de détermination de commande d'avance temporelle, dispositif terminal et dispositif de réseau
US10462827B2 (en) Random access method and apparatus
CN119854852A (zh) 无线通信的方法和通信装置
US20240179750A1 (en) Random access method and apparatus
WO2024082634A1 (fr) Procédé de positionnement, dispositif terminal et dispositif réseau
WO2023207657A1 (fr) Procédés de commande de processus d'accès aléatoire et dispositif associé
CN118283718A (zh) 通信方法和通信装置
WO2023193546A1 (fr) Procédé et appareil de communication, et support de stockage
WO2025227784A1 (fr) Procédé et appareil de mise à jour de message de système, et système associé
WO2026020937A1 (fr) Procédé de communication sans fil et appareil de communication
EP4576874A1 (fr) Procédé de transfert intercellulaire de cellule et appareil de communication
WO2023207776A1 (fr) Procédé et appareil de communication, puce et dispositif de module
WO2025035361A1 (fr) Procédé de communication sans fil et dispositif associé

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 25843326

Country of ref document: EP

Kind code of ref document: A1